ppc: fix strncasecmp prototype

Match, Linus's fix to arch/powerpc in arch/ppc. strcasecmp takes a size_t,
not an int, as its third argument.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/ppc/lib/strcase.c

@@ -11,7 +11,7 @@ int strcasecmp(const char *s1, const char *s2)
 	return c1 - c2;
 }
 
-int strncasecmp(const char *s1, const char *s2, int n)
+int strncasecmp(const char *s1, const char *s2, size_t n)
 {
 	int c1, c2;