checkpatch: add test for #defines of ARCH_HAS_<foo>

Add a test for these #defines

Additionally, moved string_find_replace sub as it screws up subsequent
formatting when placed inside another sub.

Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>