soc/intel/{cnl,icl,skl}: Convert 'platform.asl' to ASL 2.0 syntax

Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Change-Id: I3fcd971402e540d91a7392ca58175eb3ecc24cec
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45981
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/cannonlake/acpi/platform.asl

@@ -16,5 +16,5 @@
 Method (_PIC, 1)
 {
 	/* Remember the OS' IRQ routing choice. */
-	Store (Arg0, PICM)
+	PICM = Arg0
 }

src/soc/intel/icelake/acpi/platform.asl

@@ -16,5 +16,5 @@
 Method (_PIC, 1)
 {
 	/* Remember the OS' IRQ routing choice. */
-	Store (Arg0, PICM)
+	PICM = Arg0
 }

src/soc/intel/skylake/acpi/platform.asl

@@ -16,5 +16,5 @@
 Method (_PIC, 1)
 {
 	/* Remember the OS' IRQ routing choice. */
-	Store (Arg0, PICM)
+	PICM = Arg0
 }