ec/google/wilco/acpi: Read message when notifying UCSI

Allows the EC to be properly notified of type-c events like charger
wattage too low (eg),

TEST=build/boot Win11, Linux 6.x on google/drallion

Change-Id: I7a4130cf6f8c24e3f91e327adf1f3e563322c0af
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77282
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: CoolStar <coolstarorganization@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

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

@@ -141,6 +141,9 @@ Method (_Q79, 0, Serialized)
 {
 	If (ISSX == 0) {
 		Printf ("EC _Q79 UCSI Event")
+
+		\_SB.UCSI.RMSG()
+
 		Notify (\_SB.UCSI, 0x80)
 		^UCEP = 0
 	} Else {

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

@@ -124,6 +124,14 @@ Scope (\_SB)
 				}
 				Case (2)
 				{
+					/* Read Message In */
+					RMSG()
+				}
+			}
+			Return (Buffer (1) { 0 })
+		}
+
+		Method (RMSG, 0, Serialized){
 			/* Read Message In */
 			^MGI0 = R (^^UMI0)
 			^MGI1 = R (^^UMI1)
@@ -149,7 +157,4 @@ Scope (\_SB)
 			^CCI3 = R (^^UCI3)
 		}
 	}
-			Return (Buffer (1) { 0 })
-		}
-	}
 }