drm/xe/migrate: fix job lock assert

drm/xe/migrate: fix job lock assert

We are meant to be checking the user vm for the bind queue, but actually
we are checking the migrate vm. For various reasons this is not
currently firing but this will likely change in the future.

Now that we have the user_vm attached to the bind queue, we can fix this
by directly checking that here.

Fixes: dba89840a920 ("drm/xe: Add GT TLB invalidation jobs")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Arvind Yadav <arvind.yadav@intel.com>
Link: https://patch.msgid.link/20260120110609.77958-4-matthew.auld@intel.com