drm/i915: Introduce intel_crtc_planes_update_arm()

No reason the high level intel_update_crtc() needs to know
that there is something magical about the commit order of
planes between different platforms. So let's hide that
detail even better.

In order to keep to somewhat consistent naming between
things we shall call this intel_crtc_planes_update_arm()
to match the plane->update_arm() vfunc naming convention.
And let's rename the noarm counterpart to
intel_crtc_planes_update_noarm() to more clearly associate
it with the plane->update_noarm() vfunc.

v2: Change the naming convention a bit

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220216232806.6194-2-ville.syrjala@linux.intel.com