drm/i915/ips: Add i915_ips_false_color debugfs file

Similar to FBC let's expose an debugfs file to control
IPS false color. Enabling this provides an immediate visual
feedback on whether IPS is working or not.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230327133942.22063-2-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f0f7b57..4315053 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1397,7 +1397,8 @@
 #define IVB_FBC_RT_BASE_UPPER		_MMIO(0x7024)
 
 #define IPS_CTL		_MMIO(0x43408)
-#define   IPS_ENABLE	(1 << 31)
+#define   IPS_ENABLE		REG_BIT(31)
+#define   IPS_FALSE_COLOR	REG_BIT(4)
 
 #define MSG_FBC_REND_STATE(fbc_id)	_MMIO_PIPE((fbc_id), 0x50380, 0x50384)
 #define   FBC_REND_NUKE			REG_BIT(2)