kconfig: use memcmp instead of deprecated bcmp

bcmp() was removed in POSIX.1-2008.

This commit replaces bcmp() with memcmp(). This allows Kconfig to link
with C libraries that do not provide bcmp(), such as Android bionic
libc.

Signed-off-by: Thomas Meyer <[e-mail]>
Reviewed-by: Miguel Ojeda <[e-mail]>
Reported-by: Abhigyan Ghosh <[e-mail]>
[masahiro: update commit description]
Signed-off-by: Masahiro Yamada <[e-mail]>

scripts/kconfig/confdata.c

···
 	if (map2 == MAP_FAILED)
 		goto close2;
 
-	if (bcmp(map1, map2, st1.st_size))
+	if (memcmp(map1, map2, st1.st_size))
 		goto close2;
 
 	ret = true;