drm/xe: memirq handler changes

Expose an interrupt processing handler for a single hw engine.
Refactor code to use this handler from the VF.
This handler also caters for the MSI-X mode, where the hardware engines
report interrupt source and status to the offset of engine instance zero
(this usage will be introduced in upcoming MSI-X enabling series).

Signed-off-by: Ilia Levi <ilia.levi@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240918053942.1331811-6-illevi@habana.ai