mips: fix setup_zero_pages() prototype

setup_zero_pages() has a local declaration in a platform specific header,
but that is not seen in the file it is defined in:

arch/mips/mm/init.c:60:6: error: no previous prototype for 'setup_zero_pages' [-Werror=missing-prototypes]

Move it to the corresponding global header and include that where 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/mach-loongson64/mmzone.h

···
 
 #define NODE_DATA(n)		(__node_data[n])
 
-extern void setup_zero_pages(void);
 extern void __init prom_init_numa_memory(void);
 
 #endif /* _ASM_MACH_MMZONE_H */

arch/mips/include/asm/mmzone.h

···
 #define nid_to_addrbase(nid) 0
 #endif
 
+extern void setup_zero_pages(void);
+
 #endif /* _ASM_MMZONE_H_ */

arch/mips/mm/init.c

···
 #include <asm/dma.h>
 #include <asm/maar.h>
 #include <asm/mmu_context.h>
+#include <asm/mmzone.h>
 #include <asm/sections.h>
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>