quota: correct error number in free_dqentry()

Fix the error path in free_dqentry(), pass out the error number if the
block to free is not correct.

Fixes: 1ccd14b9 ("quota: Split off quota tree handling into a separate file")
Link: https://lore.kernel.org/r/20211008093821.1001186-3-yi.zhang@huawei.com


Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>