drm/xe/xe2: Update render/compute context image sizes

drm/xe/xe2: Update render/compute context image sizes

The render and compute context are significantly smaller on Xe2 than on
previous platforms.

Registers:
 - Render:  3008 dwords -> 12032 bytes -> round to 3 pages
 - Compute: 1424 dwords ->  5696 bytes -> round to 2 pages

We also allocate one additional page for the HWSP, so the total
allocation sizes for render and compute are 4 and 3 pages respectively.

Bspec: 65182, 56578, 55793
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Atwood <matthew.s.atwood@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>