drm/i915/xehp: compute engine pipe_control

CCS will reuse the RCS functions for breadcrumb and flush emission.
However, CCS pipe_control has additional programming restrictions:
 - Command Streamer Stall Enable must be always set
 - Post Sync Operations must not be set to Write PS Depth Count
 - 3D-related bits must not be set

v2:
 - Drop unwanted blank line.  (Lucas)

Bspec: 47112
Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220301231549.1817978-5-matthew.d.roper@intel.com