ffs: do not use _inline versions of find_[first|last]_set

Standardize on using the find_[first|last]_set (non-inline) symbols
everywhere.

The non-inline versions provide absolutely no benefits, so they will be
removed in a subsequent commit, and the inline versions will have their
_inline suffix removed.

Change-Id: I5b3dee33ffe3878a05e1bb3c6400a8d8c1640ad4
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>