gfs2: Don't forget to complete delayed withdraw

gfs2: Don't forget to complete delayed withdraw

[ Upstream commit b01189333ee91c1ae6cd96dfd1e3a3c2e69202f0 ]

Commit fffe9bee14b0 ("gfs2: Delay withdraw from atomic context")
switched from gfs2_withdraw() to gfs2_withdraw_delayed() in
gfs2_ail_error(), but failed to then check if a delayed withdraw had
occurred.  Fix that by adding the missing check in __gfs2_ail_flush(),
where the spin locks are already dropped and a withdraw is possible.

Fixes: fffe9bee14b0 ("gfs2: Delay withdraw from atomic context")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>