gfs2: Revert "Fix loop in gfs2_rbm_find"

gfs2: Revert "Fix loop in gfs2_rbm_find"

This reverts commit 989776fe820b9f06e885f4fc29427d39b1a3f41a.

It turns out that the fix can lead to a ~20 percent performance regression
in initial writes to the page cache according to iozone.  Let's revert this
for now to have more time for a proper fix.

Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>