rockchip64/rk3318-box: move stack further from base addr to allow bigger uboot image

Author: alex3d

patch/u-boot/v2024.01/board_rk3318-box/rk3318-box-add-defconfig.patch

@@ -11,7 +11,7 @@ index 0000000000..d356b21ac6
 +CONFIG_TEXT_BASE=0x200000
 +CONFIG_NR_DRAM_BANKS=1
 +CONFIG_HAS_CUSTOM_SYS_INIT_SP_ADDR=y
-+CONFIG_CUSTOM_SYS_INIT_SP_ADDR=0x300000
++CONFIG_CUSTOM_SYS_INIT_SP_ADDR=0xc00000
 +CONFIG_SF_DEFAULT_SPEED=20000000
 +CONFIG_ENV_OFFSET=0x3F8000
 +CONFIG_DEFAULT_DEVICE_TREE="rk3318-box"