drm/xe/vm: Simplify if condition

The if condition !A || A && B can be simplified to !A || B.

Fixes the following Coccinelle/coccicheck warning reported by
excluded_middle.cocci:

	WARNING !A || A && B is equivalent to !A || B

Compile-tested only.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240603180005.191578-1-thorsten.blum@toblux.com