[Intel-gfx] Fixes that failed to apply to v5.6-rc3

[Jani Nikula]

Hi all -

The following commits have been marked as Cc: stable or fixing something
in v5.6-rc3 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.

Failed to cherry-pick:
837b63e60878 ("drm/i915: Program MBUS with rmw during initialization")
87e04f75928b ("drm/i915/tgl: Add Wa_22010178259:tgl")
df1a5bfc16f3 ("drm/i915/psr: Force PSR probe only after full initialization")

This one was fine to cherry-pick, but caused problematic (for me!)
conflicts in drm-tip rebuild:
42fb60de3129 ("drm/i915/gem: Don't leak non-persistent requests on changing engines")

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Graphics Center