mb/lenovo/x1_carbon_gen1/acpi: call MUTE(1) and USBP(0) on _PTS

Like with any other Thinkpad, call MUTE(1) and USBP(0) on _PTS on the
Lenovo Thinkpad X1 Carbon 1st generation.
Without MUTE(1) the speakers sometimes glitch before going into S3 (if not
muted), while without USBP(0) the USB ports are always powered in S3,
regardless of the USB Always-On mode selected.

Change-Id: I86f3c5a72e2589c5570303bf68f39df3ef874cb8
Signed-off-by: Nicola Corna <nicola@corna.info>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31829
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/mainboard/lenovo/x1_carbon_gen1/acpi/platform.asl

@@ -19,6 +19,8 @@
 
 Method(_PTS,1)
 {
+	\_SB.PCI0.LPCB.EC.MUTE(1)
+	\_SB.PCI0.LPCB.EC.USBP(0)
 	\_SB.PCI0.LPCB.EC.RADI(0)
 }