rockchip: rk3308: allow loading larger kernel Image

When compile the curren mainline linux kernel(Linux 5.5-rc3)
with defconfig, the final Image is 29M, it's much
larger than Linux 5.4.

On the current u-boot side on rk3308, the gap between
kernel and fdt is 25M, the fdt will overwrite kernel
Image, so move ftd to a higher memory to give 34M
gab for them.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/include/configs/rk3308_common.h b/include/configs/rk3308_common.h
index a67d3d7..bd9ac82 100644
--- a/include/configs/rk3308_common.h
+++ b/include/configs/rk3308_common.h
@@ -42,7 +42,7 @@
 #define ENV_MEM_LAYOUT_SETTINGS \
 	"scriptaddr=0x00500000\0" \
 	"pxefile_addr_r=0x00600000\0" \
-	"fdt_addr_r=0x01f00000\0" \
+	"fdt_addr_r=0x02800000\0" \
 	"kernel_addr_r=0x00680000\0" \
 	"ramdisk_addr_r=0x04000000\0"