ovl: fix verity lazy-load guard broken by fsverity_active() semantic change

ovl: fix verity lazy-load guard broken by fsverity_active() semantic change

Commit f77f281b6118 ("fsverity: use a hashtable to find the
fsverity_info") made fsverity_active() check whether the inode has the
verity flag, rather than whether the inode's fsverity_info is loaded.
This broke ovl_ensure_verity_loaded(), which wants to load the
fsverity_info for any verity inodes that haven't had it loaded yet.

Therefore, to check that the fsverity_info hasn't yet been loaded, use
fsverity_get_info(inode) == NULL instead of !fsverity_active(inode).

Also, since fsverity_get_info() now involves a hash table lookup, put
the more lightweight IS_VERITY() flag check first.

Fixes: f77f281b6118 ("fsverity: use a hashtable to find the fsverity_info")
Cc: stable@vger.kernel.org
Link: https://github.com/bootc-dev/bootc/issues/2174
Signed-off-by: Colin Walters <walters@verbum.org>
Acked-by: Amir Goldstein <amir73il@gmail.com>
Link: https://patch.msgid.link/20260505224257.23213-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>