mb/google/brya/var/kano: Disable unused PCIE root port in devicetree

The baseboard enables PCIe RPs 6, 8 and 9, but kano doesn't use
these. Having them enabled will occasionally cause suspend
attempts to fail, therefore disable them in the overridetree.

BUG=b:203389490 b:192370253
TEST=FW_NAME=kano emerge-brya coreboot and verify it builds
without error.

Signed-off-by: David Wu <david_wu@quanta.corp-partner.google.com>
Change-Id: Ie2b82cff6d910c961eeb56704dcbae2bdc2a8c53
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58566
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: YH Lin <yueherngl@google.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/mainboard/google/brya/variants/kano/overridetree.cb

@@ -389,6 +389,9 @@ chip soc/intel/alderlake
 				device i2c 0x2c on end
 			end
 		end
+		device ref pcie_rp6 off end	# PCIE6 WWAN
+		device ref pcie_rp8 off end	# PCIE8 SD card
+		device ref pcie_rp9 off end	# PCIE9-12 SSD
 		device ref gspi1 on
 			chip drivers/spi/acpi
 				register "name" = ""CRFP""