jbd2: remove dead check in journal_alloc_journal_head

We will alloc journal_head with __GFP_NOFAIL anyway, test for failure
is pointless.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240801013815.2393869-3-shikemeng@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>