drm/i915: Split ivb+ sprite plane update into noarm+arm pair

drm/i915: Split ivb+ sprite plane update into noarm+arm pair

Chop ivb_sprite_update() into two halves. Fist half becomes
the _noarm() variant, second part the _arm() variant.

Fortunately I have already previously grouped the register
writes into roughtly the correct order, so the split looks
surprisingly clean.

Didn't bother with i915_update_info numbers for this one.
I expect the results to be pretty much identical to the snb
numbers from the corresponding g4x+ sprite modification.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018115030.3547-9-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>