riscv: sifive: Rename fu540 board to unleashed

In preparation to add SiFive Unmatched board support, let's rename
the existing fu540 board to unleashed.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/configs/sifive_unleashed_defconfig b/configs/sifive_unleashed_defconfig
new file mode 100644
index 0000000..62416a7
--- /dev/null
+++ b/configs/sifive_unleashed_defconfig
@@ -0,0 +1,29 @@
+CONFIG_RISCV=y
+CONFIG_SPL_GPIO_SUPPORT=y
+CONFIG_SYS_MALLOC_F_LEN=0x3000
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_SPL_DM_SPI=y
+CONFIG_SPL_MMC_SUPPORT=y
+CONFIG_SPL=y
+CONFIG_SPL_SPI_FLASH_SUPPORT=y
+CONFIG_SPL_SPI_SUPPORT=y
+CONFIG_DEFAULT_DEVICE_TREE="hifive-unleashed-a00"
+CONFIG_TARGET_SIFIVE_UNLEASHED=y
+CONFIG_ARCH_RV64I=y
+CONFIG_RISCV_SMODE=y
+CONFIG_DISTRO_DEFAULTS=y
+CONFIG_FIT=y
+CONFIG_SPL_LOAD_FIT_ADDRESS=0x84000000
+CONFIG_DISPLAY_CPUINFO=y
+CONFIG_DISPLAY_BOARDINFO=y
+CONFIG_MISC_INIT_R=y
+CONFIG_SPL_SEPARATE_BSS=y
+CONFIG_SPL_DM_SPI_FLASH=y
+CONFIG_SPL_DM_RESET=y
+CONFIG_SPL_SPI_LOAD=y
+CONFIG_SPL_YMODEM_SUPPORT=y
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_SPL_DM_SEQ_ALIAS=y
+CONFIG_SPL_CLK=y
+CONFIG_DM_MTD=y
+CONFIG_DM_RESET=y