Add:
WaEnableForceRestoreInCtxtDescForVCS

v2: Add stepping check.

v3: Fixed stepping check direction. Cleaned up indentation.
Signed-off-by: Nick Hoath <nicholas.hoath@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>