powerpc/signal: Remove BUG_ON() in handler_signal functions

There is already the same BUG_ON() check in do_signal() which
is the only caller of handle_rt_signal64() handle_rt_signal32() and
handle_signal32().

Remove those three redundant BUG_ON().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3582e10a341d523c9c3f1ac925c3aaefc9d9293d.1597770847.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/signal_32.c

@@ -764,8 +764,6 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	unsigned long msr = regs->msr;
 #endif
 
-	BUG_ON(tsk != current);
-
 	/* Set up Signal Frame */
 	/* Put a Real Time Context onto stack */
 	rt_sf = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*rt_sf), 1);
@@ -1227,8 +1225,6 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 	unsigned long msr = regs->msr;
 #endif
 
-	BUG_ON(tsk != current);
-
 	/* Set up Signal Frame */
 	frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 1);
 	if (unlikely(frame == NULL))

arch/powerpc/kernel/signal_64.c

@@ -822,8 +822,6 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	unsigned long msr = regs->msr;
 #endif
 
-	BUG_ON(tsk != current);
-
 	frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0);
 	if (unlikely(frame == NULL))
 		goto badframe;