nds32: Mark expected switch fall-throughs

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings (Building: allmodconfig nds32):

include/math-emu/soft-fp.h:124:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
arch/nds32/kernel/signal.c:362:20: warning: this statement may fall through [-Wimplicit-fallthrough=]
arch/nds32/kernel/signal.c:315:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:417:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:430:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/soft-fp.h:124:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:417:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:430:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

arch/nds32/kernel/signal.c

@@ -316,6 +316,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 				regs->uregs[0] = -EINTR;
 				break;
 			}
+			/* Else, fall through */
 		case -ERESTARTNOINTR:
 			regs->uregs[0] = regs->orig_r0;
 			regs->ipc -= 4;
@@ -360,6 +361,7 @@ static void do_signal(struct pt_regs *regs)
 		switch (regs->uregs[0]) {
 		case -ERESTART_RESTARTBLOCK:
 			regs->uregs[15] = __NR_restart_syscall;
+			/* Fall through */
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:

include/math-emu/op-common.h

@@ -308,6 +308,7 @@ do {									     \
 									     \
   case _FP_CLS_COMBINE(FP_CLS_NORMAL,FP_CLS_ZERO):			     \
     R##_e = X##_e;							     \
+	  /* Fall through */						     \
   case _FP_CLS_COMBINE(FP_CLS_NAN,FP_CLS_NORMAL):			     \
   case _FP_CLS_COMBINE(FP_CLS_NAN,FP_CLS_INF):				     \
   case _FP_CLS_COMBINE(FP_CLS_NAN,FP_CLS_ZERO):				     \
@@ -318,6 +319,7 @@ do {									     \
 									     \
   case _FP_CLS_COMBINE(FP_CLS_ZERO,FP_CLS_NORMAL):			     \
     R##_e = Y##_e;							     \
+	  /* Fall through */						     \
   case _FP_CLS_COMBINE(FP_CLS_NORMAL,FP_CLS_NAN):			     \
   case _FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_NAN):				     \
   case _FP_CLS_COMBINE(FP_CLS_ZERO,FP_CLS_NAN):				     \
@@ -415,6 +417,7 @@ do {							\
   case _FP_CLS_COMBINE(FP_CLS_NAN,FP_CLS_INF):		\
   case _FP_CLS_COMBINE(FP_CLS_NAN,FP_CLS_ZERO):		\
     R##_s = X##_s;					\
+	/* Fall through */				\
 							\
   case _FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_INF):		\
   case _FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_NORMAL):	\
@@ -428,6 +431,7 @@ do {							\
   case _FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_NAN):		\
   case _FP_CLS_COMBINE(FP_CLS_ZERO,FP_CLS_NAN):		\
     R##_s = Y##_s;					\
+	/* Fall through */				\
 							\
   case _FP_CLS_COMBINE(FP_CLS_NORMAL,FP_CLS_INF):	\
   case _FP_CLS_COMBINE(FP_CLS_NORMAL,FP_CLS_ZERO):	\
@@ -493,6 +497,7 @@ do {							\
 							\
   case _FP_CLS_COMBINE(FP_CLS_NORMAL,FP_CLS_ZERO):	\
     FP_SET_EXCEPTION(FP_EX_DIVZERO);			\
+	  /* Fall through */				\
   case _FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_ZERO):		\
   case _FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_NORMAL):	\
     R##_c = FP_CLS_INF;					\