drm/xe: Define registers used by memory based irq processing

drm/xe: Define registers used by memory based irq processing

The RING_INT_SRC_RPT_PTR register points to a cacheline in memory
to which an engine must report as source of interrupt prior to
generating an interrupt to the host.

The RING_INT_STATUS_RPT_PTR register points to the first cacheline
of the Interrupt Status Report (ISR) page (4KB) in graphics memory
to which all engines report their interrupt status.

The RING_IMR register has the interrupt enables and interrupt masks
for an engine.

We will refer to these registers shortly.

Bspec: 45963, 45964, 45965
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20231214185955.1791-3-michal.wajdeczko@intel.com
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>