board: sifive: add HiFive Unmatched board support

Add defconfig and board support for HiFive Unmatched.

Signed-off-by: Green Wan <green.wan@sifive.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index b709a05..fa80524 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -322,7 +322,7 @@
 		     ARCH_ROCKCHIP || ARCH_MVEBU ||  ARCH_SOCFPGA || \
 		     ARCH_AT91 || ARCH_ZYNQ || ARCH_KEYSTONE || OMAP34XX || \
 		     OMAP44XX || OMAP54XX || AM33XX || AM43XX || \
-		     TARGET_SIFIVE_UNLEASHED
+		     TARGET_SIFIVE_UNLEASHED || TARGET_SIFIVE_UNMATCHED
 	help
 	  Use sector number for specifying U-Boot location on MMC/SD in
 	  raw mode.
@@ -339,7 +339,7 @@
 	default 0x300 if ARCH_ZYNQ || ARCH_KEYSTONE || OMAP34XX || OMAP44XX || \
 		         OMAP54XX || AM33XX || AM43XX || ARCH_K3
 	default 0x4000 if ARCH_ROCKCHIP
-	default 0x822 if TARGET_SIFIVE_UNLEASHED
+	default 0x822 if TARGET_SIFIVE_UNLEASHED || TARGET_SIFIVE_UNMATCHED
 	help
 	  Address on the MMC to load U-Boot from, when the MMC is being used
 	  in raw mode. Units: MMC sectors (1 sector = 512 bytes).