mb/google/cyan: convert to overridetree

Simply cyan variants by converting to overridetree format.

A few differences were ignored as there appears to be no
reason behind them:

- cyan had PCIe RP2 enabled, but nothing is attached to it
- kefka had the SPI 1 device disabled
- reks, relm, and ultima had HSUART 1 disabled
- edgar had I2C1 UPD disabled

Test: build/boot cyan and edgar variants, verify everything
still works

Change-Id: I9928cc59adcfda4661ddfdfa95f53a7820053b4a
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39964
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/cyan/Kconfig b/src/mainboard/google/cyan/Kconfig
index 45610542..92bafee 100644
--- a/src/mainboard/google/cyan/Kconfig
+++ b/src/mainboard/google/cyan/Kconfig
@@ -68,9 +68,9 @@
 	default "Ultima" if BOARD_GOOGLE_ULTIMA
 	default "Wizpig" if BOARD_GOOGLE_WIZPIG
 
-config DEVICETREE
+config OVERRIDE_DEVICETREE
 	string
-	default "variants/$(CONFIG_VARIANT_DIR)/devicetree.cb"
+	default "variants/$(CONFIG_VARIANT_DIR)/overridetree.cb"
 
 config CBFS_SIZE
 	hex