drm/i915/display: Add definition for wcl as subplatform

We will need to differentiate between WCL and PTL in
intel_encoder_is_c10phy(). Since WCL and PTL use the same display
architecture, let's define WCL as a subplatform of PTL to allow the
differentiation.

v2: Update commit message and reorder wcl define (Gustavo)

Fixes: 3c0f211 ("drm/xe: Add Wildcat Lake device IDs to PTL list")
Signed-off-by: Dnyaneshwar Bhadane <dnyaneshwar.bhadane@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://lore.kernel.org/r/20250922150317.2334680-3-dnyaneshwar.bhadane@intel.com
(cherry picked from commit 4dfaae6)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Rodrigo added Fixes tag when porting it to fixes]

Author: bhadanednyaneshwar

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

@@ -1404,8 +1404,20 @@ static const struct platform_desc bmg_desc = {
 	PLATFORM_GROUP(dgfx),
 };
 
+static const u16 wcl_ids[] = {
+	INTEL_WCL_IDS(ID),
+	0
+};
+
 static const struct platform_desc ptl_desc = {
 	PLATFORM(pantherlake),
+	.subplatforms = (const struct subplatform_desc[]) {
+		{
+			SUBPLATFORM(pantherlake, wildcatlake),
+			.pciidlist = wcl_ids,
+		},
+		{},
+	}
 };
 
 __diag_pop();

drivers/gpu/drm/i915/display/intel_display_device.h

@@ -101,7 +101,9 @@ struct pci_dev;
 	/* Display ver 14.1 (based on GMD ID) */ \
 	func(battlemage) \
 	/* Display ver 30 (based on GMD ID) */ \
-	func(pantherlake)
+	func(pantherlake) \
+	func(pantherlake_wildcatlake)
+
 
 #define __MEMBER(name) unsigned long name:1;
 #define __COUNT(x) 1 +