MIPS: BCM47XX: Cast memcmp() of function to (void *)

[ Upstream commit 0dedcf6 ]

Clang is especially sensitive about argument type matching when using
__overloaded functions (like memcmp(), etc). Help it see that function
pointers are just "void *". Avoids this error:

arch/mips/bcm47xx/prom.c:89:8: error: no matching function for call to 'memcmp'
                   if (!memcmp(prom_init, prom_init + mem, 32))
                        ^~~~~~
include/linux/string.h:156:12: note: candidate function not viable: no known conversion from 'void (void)' to 'const void *' for 1st argument extern int memcmp(const void *,const void *,__kernel_size_t);

Cc: Hauke Mehrtens <[email protected]>
Cc: "Rafał Miłecki" <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: [email protected]
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: [email protected]
Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: kees

arch/mips/bcm47xx/prom.c

@@ -85,7 +85,7 @@ static __init void prom_init_mem(void)
 			pr_debug("Assume 128MB RAM\n");
 			break;
 		}
-		if (!memcmp(prom_init, prom_init + mem, 32))
+		if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32))
 			break;
 	}
 	lowmem = mem;
@@ -162,7 +162,7 @@ void __init bcm47xx_prom_highmem_init(void)
 
 	off = EXTVBASE + __pa(off);
 	for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) {
-		if (!memcmp(prom_init, (void *)(off + extmem), 16))
+		if (!memcmp((void *)prom_init, (void *)(off + extmem), 16))
 			break;
 	}
 	extmem -= lowmem;