gfs2: Revert "Fix loop in gfs2_rbm_find"

gfs2: Revert "Fix loop in gfs2_rbm_find"

This reverts commit 2d29f6b96d8f80322ed2dd895bca590491c38d34.

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>