mips: move build_tlb_refill_handler() prototype

Instead of having a declaration for each caller, have one that is shared
with the function definition, which avoids a warning:

arch/mips/mm/tlbex.c:2547:6: error: no previous prototype for 'build_tlb_refill_handler' [-Werror=missing-prototypes]

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnd Bergmann <[e-mail]>
Cc: Stephen Rothwell <[e-mail]>
Cc: Thomas Bogendoerfer <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

arch/mips/include/asm/tlbex.h

···
 void build_tlb_write_entry(u32 **p, struct uasm_label **l,
 			   struct uasm_reloc **r,
 			   enum tlb_write_entry wmode);
+void build_tlb_refill_handler(void);
 
 extern void handle_tlbl(void);
 extern char handle_tlbl_end[];

arch/mips/mm/tlb-r3k.c

···
 #include <asm/io.h>
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/tlbex.h>
 
 #undef DEBUG_TLB
-
-extern void build_tlb_refill_handler(void);
 
 /* CP0 hazard avoidance. */
 #define BARRIER				\

arch/mips/mm/tlb-r4k.c

···
 #include <asm/hazards.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
+#include <asm/tlbex.h>
 #include <asm/tlbmisc.h>
-
-extern void build_tlb_refill_handler(void);
 
 /*
  * LOONGSON-2 has a 4 entry itlb which is a subset of jtlb, LOONGSON-3 has