ext4: unify SYNC mode checks in fallocate paths

ext4: unify SYNC mode checks in fallocate paths

In the ext4 fallocate call chain, SYNC mode handling is inconsistent:
some places check the inode state, while others check the open file
descriptor state. Unify these checks by evaluating both conditions
to ensure consistent behavior across all fallocate operations.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260327102939.1095257-11-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>