drm/xe: Enable Coarse Power Gating

Enable power gating for all units and sub-pipes that
are disabled by default.

v2: change the init function name
    use symmetric calls for enable/disable pg
    re-pharase commit message (Rodrigo)
    modify the sub-pipe power gating condition

v3: set hysteresis value for render and media
    when GuC PC is disabled
    skip CPG for PVC (Vinay)

v4: rebase

Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> #v2
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240524070916.143022-3-riana.tauro@intel.com


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>