ec/google/wilco/acpi: Add DPTF RCDP() method

The Windows DPTF drivers expect this method, and if not present appear
to hang. Adding this method fixes DPTF under Windows on drallion.

Modeled after existing method used by chrome-ec.

TEST=build/boot Win11 on google/drallion, verify DPTF functional.

Change-Id: I6570345379da413273251ecf5209c4997aac9b11
Original-patch-by: Coolstar <coolstarorganization@gmail.com>
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/72578
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Caveh Jalali <caveh@chromium.org>

src/ec/google/wilco/acpi/dptf.asl

@@ -116,3 +116,18 @@ Method (PATX, 0, Serialized)
 	/* Clear sensor events */
 	W (DWTQ, Local0)
 }
+
+#ifdef EC_ENABLE_MULTIPLE_DPTF_PROFILES
+/*
+ * Read current Device DPTF Profile Number
+ */
+Method (RCDP, 0, NotSerialized)
+{
+	Local0 = R(DRTI)
+	If (Local0 == 0) {
+		Return (R(OTBL))
+	} else {
+		Return (Local0 - 1)
+	}
+}
+#endif