arm: dts: keystone: Move to OF_UPSTREAM

Enable OF_UPSTREAM for Keystone boards. Remove DT files that
are now available in dts/upstream.

Signed-off-by: Andrew Davis <afd@ti.com>
Acked-by: Neha Malcom Francis <n-francis@ti.com>
diff --git a/configs/k2hk_evm_defconfig b/configs/k2hk_evm_defconfig
index 4da75d1..2e29b2f 100644
--- a/configs/k2hk_evm_defconfig
+++ b/configs/k2hk_evm_defconfig
@@ -18,7 +18,7 @@
 CONFIG_ENV_SIZE=0x40000
 CONFIG_ENV_OFFSET=0x100000
 CONFIG_SPL_DM_SPI=y
-CONFIG_DEFAULT_DEVICE_TREE="keystone-k2hk-evm"
+CONFIG_DEFAULT_DEVICE_TREE="ti/keystone/keystone-k2hk-evm"
 CONFIG_SPL_TEXT_BASE=0xC200000
 CONFIG_SPL_SERIAL=y
 CONFIG_SPL_STACK=0xc2223f4
@@ -100,3 +100,4 @@
 CONFIG_USB_XHCI_DWC3=y
 CONFIG_USB_DWC3=y
 CONFIG_USB_DWC3_GENERIC=y
+CONFIG_OF_UPSTREAM=y