configs: starfive: Enable environment in SPI flash support

On Starfive Visionfive 2, the u-boot environment settings are saved to
on-board SPI flash. Enable relative configs by default and set offset
and size according to upstream linux dts.

Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>

configs/starfive_visionfive2_defconfig

@@ -6,6 +6,15 @@ CONFIG_NR_DRAM_BANKS=1
 CONFIG_HAS_CUSTOM_SYS_INIT_SP_ADDR=y
 CONFIG_CUSTOM_SYS_INIT_SP_ADDR=0x80000000
 CONFIG_SF_DEFAULT_SPEED=100000000
+CONFIG_ENV_SUPPORT=y
+CONFIG_SAVEENV=y
+CONFIG_ENV_OVERWRITE=y
+CONFIG_ENV_IS_NOWHERE=y
+CONFIG_ENV_IS_IN_SPI_FLASH=y
+CONFIG_ENV_SECT_SIZE_AUTO=y
+CONFIG_ENV_SIZE=0x10000
+CONFIG_ENV_OFFSET=0xf0000
+CONFIG_ENV_SECT_SIZE=0x10000
 CONFIG_SPL_DM_SPI=y
 CONFIG_DEFAULT_DEVICE_TREE="jh7110-starfive-visionfive-2"
 CONFIG_SPL_TEXT_BASE=0x8000000