modpost: reuse ARRAY_SIZE() macro for section_mismatch()

Move ARRAY_SIZE() from file2alias.c to modpost.h to reuse it in
section_mismatch().

Also, move the variable 'check' inside the for-loop.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

scripts/mod/modpost.h

@@ -97,6 +97,9 @@ static inline void __endian(const void *src, void *dest, unsigned int size)
 #endif
 
 #define NOFAIL(ptr)   do_nofail((ptr), #ptr)
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
 void *do_nofail(void *ptr, const char *expr);
 
 struct buffer {