drm/xe/xe2hpg: Remove extra allocation of CCS pages for dgfx

On Xe2 dGPU, compression is only supported with VRAM. When copying from
VRAM -> system memory the KMD uses mapping with uncompressed PAT
so the copy in system memory is guaranteed to be uncompressed.
When restoring such buffers from system memory -> VRAM the KMD can't
easily know which pages were originally compressed, so we always use
uncompressed -> uncompressed here.
so this means that there's no need for extra CCS storage on such
platforms.

v2: More description added to commit message

Signed-off-by: Akshata Jahagirdar <akshata.jahagirdar@intel.com>
Signed-off-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240408170545.3769566-8-balasubramani.vivekanandan@intel.com