powerpc/setup_64: Make some routines static

The following routines are only called by local services and do not
need to be external symbols.

It fixes these W=1 errors :

../arch/powerpc/kernel/setup_64.c:261:13: error: no previous prototype for ‘record_spr_defaults’ [-Werror=missing-prototypes]
  261 | void __init record_spr_defaults(void)
      |             ^~~~~~~~~~~~~~~~~~~
../arch/powerpc/kernel/setup_64.c:1011:6: error: no previous prototype for ‘entry_flush_enable’ [-Werror=missing-prototypes]
 1011 | void entry_flush_enable(bool enable)
      |      ^~~~~~~~~~~~~~~~~~
../arch/powerpc/kernel/setup_64.c:1023:6: error: no previous prototype for ‘uaccess_flush_enable’ [-Werror=missing-prototypes]
 1023 | void uaccess_flush_enable(bool enable)
      |      ^~~~~~~~~~~~~~~~~~~~
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210104143206.695198-7-clg@kaod.org

arch/powerpc/kernel/setup_64.c

@@ -67,6 +67,7 @@
 #include <asm/kup.h>
 #include <asm/early_ioremap.h>
 #include <asm/pgalloc.h>
+#include <asm/asm-prototypes.h>
 
 #include "setup.h"
 
@@ -258,7 +259,7 @@ static void cpu_ready_for_interrupts(void)
 
 unsigned long spr_default_dscr = 0;
 
-void __init record_spr_defaults(void)
+static void __init record_spr_defaults(void)
 {
 	if (early_cpu_has_feature(CPU_FTR_DSCR))
 		spr_default_dscr = mfspr(SPRN_DSCR);
@@ -1008,7 +1009,7 @@ void rfi_flush_enable(bool enable)
 	rfi_flush = enable;
 }
 
-void entry_flush_enable(bool enable)
+static void entry_flush_enable(bool enable)
 {
 	if (enable) {
 		do_entry_flush_fixups(enabled_flush_types);
@@ -1020,7 +1021,7 @@ void entry_flush_enable(bool enable)
 	entry_flush = enable;
 }
 
-void uaccess_flush_enable(bool enable)
+static void uaccess_flush_enable(bool enable)
 {
 	if (enable) {
 		do_uaccess_flush_fixups(enabled_flush_types);