rockchip: rk3399: Migrate to OF_UPSTREAM

All RK3399 boards has now been synced to Linux kernel v6.8 DTs and can
migrate to use OF_UPSTREAM.

Migrate RK3399 boards that exists in Linux v6.8 to use OF_UPSTREAM.

Following target is not migrated to use OF_UPSTREAM:
- nanopi-m4-2gb-rk3399: DDR3 variant of nanopi-m4-rk3399 (LPDDR3)

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
index a492b08..a2c8148 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -272,6 +272,7 @@
 	imply MISC_INIT_R
 	imply OF_LIBFDT_OVERLAY
 	imply OF_LIVE
+	imply OF_UPSTREAM
 	imply PARTITION_TYPE_GUID
 	imply PHY_GIGE if GMAC_ROCKCHIP
 	imply PRE_CONSOLE_BUFFER