drm/xe/gt: Add engine masks for each class

drm/xe/gt: Add engine masks for each class

Follow up patches will need the engine masks for VCS and VECS engines.
Since we already have a macro for the CCS engines, just extend the same
approach to all classes.

To avoid confusion with the XE_HW_ENGINE_*_MASK masks, the new macros
use the _INSTANCES suffix instead. For consistency, rename CCS_MASK to
CCS_INSTANCES as well.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20251218223846.1146344-15-daniele.ceraolospurio@intel.com