mb/google/volteer: Add PMC.MUX.CONx devices to devicetree for Volteer

Volteer's MUX connections are known, and can now be described in ACPI
tables. Port 1 has the only oddity, with SBU lines staying fixed in the
CC1 orientation.

TEST=Dump SSDT tables on Volteer, and confirm (coalesced for brevity):

Scope (\_SB.PCI0.PMC)
{
        Device (MUX)
        {
                Name (_HID, "INTC105C")
                Device (CON0)
                {
                        Name (_ADR, 0)
                        Name (_DSD, Package() {
                                Package () { "usb2-port-number", 9 },
                                Package () { "usb3-port-number", 1 },
                        })
                }
		Device (CON1)
		{
			Name (_ADR, 1)
                        Name (_DSD, Package() {
				Package () { "usb2-port-number", 4 },
                                Package () { "usb3-port-number", 2 },
                                Package () { "sbu-orientation", "normal" },
				...
		}
        }
}

Change-Id: Id361b2df07e87ad72b6a59a686977b3f424e8ecf
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41414
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/mainboard/google/volteer/Kconfig

@@ -5,6 +5,7 @@ config BOARD_GOOGLE_BASEBOARD_VOLTEER
 	select DRIVERS_I2C_GENERIC
 	select DRIVERS_I2C_HID
 	select DRIVERS_I2C_SX9310
+	select DRIVERS_INTEL_PMC
 	select DRIVERS_INTEL_SOUNDWIRE
 	select DRIVERS_SPI_ACPI
 	select DRIVERS_SOUNDWIRE_ALC5682

src/mainboard/google/volteer/variants/volteer/overridetree.cb

@@ -21,5 +21,26 @@ chip soc/intel/tigerlake
 				end
 			end
 		end
+		device pci 1f.2 hidden
+			# The pmc_mux chip driver is a placeholder for the
+			# PMC.MUX device in the ACPI hierarchy.
+			chip drivers/intel/pmc_mux
+				device generic 0 on
+					chip drivers/intel/pmc_mux/con
+						register "usb2_port_number" = "9"
+						register "usb3_port_number" = "1"
+						# SBU & HSL follow CC
+						device generic 0 on end
+					end
+					chip drivers/intel/pmc_mux/con
+						register "usb2_port_number" = "4"
+						register "usb3_port_number" = "2"
+						# SBU is fixed, HSL follows CC
+						register "sbu_orientation" = "TYPEC_ORIENTATION_NORMAL"
+						device generic 1 on end
+					end
+				end
+			end
+		end # PMC
 	end
 end