[Intel-gfx] Fixes that failed to apply to v5.11-rc4

[Jani Nikula]

The following commits have been marked as Cc: stable or fixing something
in v5.11-rc4 or earlier, but failed to cherry-pick to
drm-intel-fixes. Please see if they are worth backporting, and please do
so if they are.

Conflicts:
dbe13ae1d6ab ("drm/i915/pmu: Don't grab wakeref when enabling events")
9bb36cf66091 ("drm/i915: Check for rq->hwsp validity after acquiring RCU lock")
5b4dc95cf7f5 ("drm/i915/gt: Prevent use of engine->wa_ctx after error")
6a3daee1b38e ("drm/i915/selftests: Fix some error codes")
67fba3f1c73b ("drm/i915/dp: Fix LTTPR vswing/pre-emp setting in non-transparent mode")

Fails to build:
3170a21f7059 ("drm/i915: Only enable DFP 4:4:4->4:2:0 conversion when outputting YCbCr 4:4:4")

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Graphics Center