configs: rockchip: imply OF_LIBFDT_OVERLAY for rk3308 and rk3328

for rk3308, all defconfigs have CONFIG_OF_LIBFDT_OVERLAY=y, so enable it
by default.

for rk3328, any defconfig doesn't have it. but there is no strong reason
not to enable it. at least it's required for ROCK Pi E.

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

arch/arm/mach-rockchip/Kconfig

@@ -169,6 +169,7 @@ config ROCKCHIP_RK3308
 	imply LEGACY_IMAGE_FORMAT
 	imply MISC
 	imply MISC_INIT_R
+	imply OF_LIBFDT_OVERLAY
 	imply OF_UPSTREAM
 	imply RNG_ROCKCHIP
 	imply ROCKCHIP_COMMON_BOARD
@@ -199,6 +200,7 @@ config ROCKCHIP_RK3328
 	imply ARMV8_SET_SMPEN
 	imply MISC
 	imply MISC_INIT_R
+	imply OF_LIBFDT_OVERLAY
 	imply OF_LIVE
 	imply OF_UPSTREAM
 	imply PRE_CONSOLE_BUFFER

configs/evb-rk3308_defconfig

@@ -3,7 +3,6 @@ CONFIG_SKIP_LOWLEVEL_INIT=y
 CONFIG_COUNTER_FREQUENCY=24000000
 CONFIG_ARCH_ROCKCHIP=y
 CONFIG_DEFAULT_DEVICE_TREE="rockchip/rk3308-evb"
-CONFIG_OF_LIBFDT_OVERLAY=y
 CONFIG_DM_RESET=y
 CONFIG_ROCKCHIP_RK3308=y
 CONFIG_TARGET_EVB_RK3308=y

configs/roc-cc-rk3308_defconfig

@@ -4,7 +4,6 @@ CONFIG_COUNTER_FREQUENCY=24000000
 CONFIG_ARCH_ROCKCHIP=y
 CONFIG_SPL_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="rockchip/rk3308-roc-cc"
-CONFIG_OF_LIBFDT_OVERLAY=y
 CONFIG_DM_RESET=y
 CONFIG_ROCKCHIP_RK3308=y
 CONFIG_TARGET_ROC_RK3308_CC=y

configs/rock-pi-s-rk3308_defconfig

@@ -3,7 +3,6 @@ CONFIG_SKIP_LOWLEVEL_INIT=y
 CONFIG_COUNTER_FREQUENCY=24000000
 CONFIG_ARCH_ROCKCHIP=y
 CONFIG_DEFAULT_DEVICE_TREE="rockchip/rk3308-rock-pi-s"
-CONFIG_OF_LIBFDT_OVERLAY=y
 CONFIG_DM_RESET=y
 CONFIG_ROCKCHIP_RK3308=y
 CONFIG_TARGET_EVB_RK3308=y