drm/i915/adl_p: Also disable underrun recovery with MSO

One of the cases that the bspec lists for when underrun recovery must be
disabled is "COG;" that note actually refers to eDP multi-segmented
operation (MSO).  Let's ensure the this additional restriction is
honored by the driver.

Bspec: 50351
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Fixes: ba3b049f ("drm/i915/adl_p: Allow underrun recovery when possible")
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210816204112.2960624-1-matthew.d.roper@intel.comReviewed-by: José Roberto de Souza <jose.souza@intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -2226,6 +2226,9 @@ static bool underrun_recovery_supported(const struct intel_crtc_state *crtc_stat
 	if (crtc_state->has_psr2)
 		return false;
 
+	if (crtc_state->splitter.enable)
+		return false;
+
 	return true;
 }