jbd2: refactor wait logic for transaction updates into a common function

[ Upstream commit 4f981868 ]

No functionality change as such in this patch. This only refactors the
common piece of code which waits for t_updates to finish into a common
function named as jbd2_journal_wait_updates(journal_t *)

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/8c564f70f4b2591171677a2a74fccb22a7b6c3a4.1642416995.git.riteshh@linux.ibm.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Stable-dep-of: 2dfba3bb ("jbd2: correct the end of the journal recovery scan range")
Signed-off-by: Sasha Levin <sashal@kernel.org>