drm/i915/dsb: Always set DSB_SKIP_WAITS_EN

drm/i915/dsb: Always set DSB_SKIP_WAITS_EN

Bspec asks us to always set the DSB_SKIP_WAITS_EN bit in
DSB_CHICKEN. This seems to instruct DSB to skip vblank and
scanline waits when PSR is entered.

I don't think we have any cases currently where we would want
to enter PSR while DSB is waiting for something, but let's
set the bit anyway to align with Bspec's wishes.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306040806.21697-4-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>