drm/i915/dp: Add TPS4 PHY test pattern support

Adding support for TPS4 (CP2520 Pattern 3) PHY pattern source tests.

v2: rebase
v3:
  - Enable TPS4 only for supported platforms (Jani)
  - Uppercase in macro names (Jani)
  - Fix indentation (Jani)
  - Use drm_warn instead of WARN
v4: Disable TPS4 pattern on supported platforms only

Bspec: 50482, 50484, 7557
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Lee Shawn C <shawn.c.lee@intel.com>
Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231213211542.3585105-2-khaled.almahallawy@intel.com
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 27dc903..220fcd9 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5652,6 +5652,10 @@ enum skl_power_gate {
 #define  DP_TP_CTL_MODE_SST			(0 << 27)
 #define  DP_TP_CTL_MODE_MST			(1 << 27)
 #define  DP_TP_CTL_FORCE_ACT			(1 << 25)
+#define  DP_TP_CTL_TRAIN_PAT4_SEL_MASK		(3 << 19)
+#define  DP_TP_CTL_TRAIN_PAT4_SEL_TP4A		(0 << 19)
+#define  DP_TP_CTL_TRAIN_PAT4_SEL_TP4B		(1 << 19)
+#define  DP_TP_CTL_TRAIN_PAT4_SEL_TP4C		(2 << 19)
 #define  DP_TP_CTL_ENHANCED_FRAME_ENABLE	(1 << 18)
 #define  DP_TP_CTL_FDI_AUTOTRAIN		(1 << 15)
 #define  DP_TP_CTL_LINK_TRAIN_MASK		(7 << 8)