drm/xe: Kill xe_device_mem_access_{get*,put}

Let's simply convert all the current callers towards direct
xe_pm_runtime access and remove this extra layer of indirection.

No functional change is expected with this patch since
xe_mem_access_get was already using the xe_pm_runtime_get_noresume
at this point.

v2: Convert all the current callers instead of a big refactor
at once.

v3: - Rebased
    - Squashed the GSC/HDCP
    - Added a new case: sriov_pf_policy
    - Improved commit message to highlight that
      there's no functional change in this patch.

Reviewed-by: Matthew Auld <matthew.auld@intel.com> #v2
Cc: Suraj Kandpal <suraj.kandpal@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240418143049.43231-1-rodrigo.vivi@intel.com