mips: fix tlb_init() prototype

There are two definitions for tlb_init(), but no global declaration:

arch/mips/mm/tlb-r4k.c:552:6: error: no previous prototype for 'tlb_init' [-Werror=missing-prototypes]
arch/mips/mm/tlb-r3k.c:244:6: error: no previous prototype for 'tlb_init' [-Werror=missing-prototypes]

Move the declaration to asm/setup.h and included it as needed.

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/setup.h

···
 extern unsigned int hwrena;
 extern void per_cpu_trap_init(bool);
 extern void cpu_cache_init(void);
+extern void tlb_init(void);
 
 #endif /* __SETUP_H */

arch/mips/kernel/traps.c

···
 	return set_vi_srs_handler(n, addr, 0);
 }
 
-extern void tlb_init(void);
-
 /*
  * Timer interrupt
  */

arch/mips/mm/tlb-r3k.c

···
 #include <asm/io.h>
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/setup.h>
 #include <asm/tlbex.h>
 
 #undef DEBUG_TLB

arch/mips/mm/tlb-r4k.c

···
 #include <asm/tlb.h>
 #include <asm/tlbex.h>
 #include <asm/tlbmisc.h>
+#include <asm/setup.h>
 
 /*
  * LOONGSON-2 has a 4 entry itlb which is a subset of jtlb, LOONGSON-3 has