Revert "drm/i915/gem: Allow EXEC_CAPTURE on recoverable contexts on DG1"

This reverts commit d6e02081.

The IS_DGFX check was put in place because error capture of buffer
objects is expected to be broken on devices with VRAM.

Userspace fix[1] to the impacted media driver has been submitted, merged
and a new driver release is out as 25.2.3 where the capture flag is
dropped on DG1 thus unblocking the usage of media driver on DG1.

[1] https://github.com/intel/media-driver/commit/93c07d9b4b96a78bab21f6acd4eb863f4313ea4a



Cc: stable@vger.kernel.org # v6.0+
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Tvrtko Ursulin <tursulin@ursulin.net>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://lore.kernel.org/r/20250522064127.24293-1-joonas.lahtinen@linux.intel.com


[Joonas: Update message to point out the merged userspace fix]
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
(cherry picked from commit d2dc30e0)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>