rockchip: roc-rk3399-pc: Update ENV offset, size

Adjust the ENV offset, size to fit into all images
on 16MB flash.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/roc-pc-mezzanine-rk3399_defconfig b/configs/roc-pc-mezzanine-rk3399_defconfig
index b2c370c..f15dddc 100644
--- a/configs/roc-pc-mezzanine-rk3399_defconfig
+++ b/configs/roc-pc-mezzanine-rk3399_defconfig
@@ -1,8 +1,8 @@
 CONFIG_ARM=y
 CONFIG_ARCH_ROCKCHIP=y
 CONFIG_SYS_TEXT_BASE=0x00200000
-CONFIG_ENV_SIZE=0x6000
-CONFIG_ENV_OFFSET=0x460000
+CONFIG_ENV_SIZE=0x8000
+CONFIG_ENV_OFFSET=0x3F8000
 CONFIG_ENV_SECT_SIZE=0x1000
 CONFIG_SPL_DM_SPI=y
 CONFIG_ROCKCHIP_RK3399=y