Only buffers mapped in the GGTT used by the GuC require an invalidation.
Display buffers do not require an invalidation. Delete the invalidatio
from display code and make invalidation a static function in xe_ggtt.c.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306052002.311196-3-matthew.brost@intel.com