riscv: sifive: unleashed: Add genimage config files

This adds genimage [1] config files for generating SD card and spi-nor
images, which can be programmed to an SD card or SPI flash and boot
from there.

The same images will be used for U-Boot CI testing for this board.

[1] https://github.com/pengutronix/genimage

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/board/sifive/unleashed/genimage_sdcard.cfg b/board/sifive/unleashed/genimage_sdcard.cfg
new file mode 100644
index 0000000..91c53bf
--- /dev/null
+++ b/board/sifive/unleashed/genimage_sdcard.cfg
@@ -0,0 +1,19 @@
+image sdcard.img {
+	size = 128M
+
+	hdimage {
+		gpt = true
+	}
+
+	partition u-boot-spl {
+		image = "u-boot-spl.bin"
+		offset = 17K
+		partition-type-uuid = 5B193300-FC78-40CD-8002-E86C45580B47
+	}
+
+	partition u-boot {
+		image = "u-boot.itb"
+		offset = 1041K
+		partition-type-uuid = 2E54B353-1271-4842-806F-E436D6AF6985
+	}
+}
diff --git a/board/sifive/unleashed/genimage_spi-nor.cfg b/board/sifive/unleashed/genimage_spi-nor.cfg
new file mode 100644
index 0000000..2e5d89b
--- /dev/null
+++ b/board/sifive/unleashed/genimage_spi-nor.cfg
@@ -0,0 +1,19 @@
+image spi-nor.img {
+	size = 32M
+
+	hdimage {
+		gpt = true
+	}
+
+	partition u-boot-spl {
+		image = "u-boot-spl.bin"
+		offset = 20K
+		partition-type-uuid = 5B193300-FC78-40CD-8002-E86C45580B47
+	}
+
+	partition u-boot {
+		image = "u-boot.itb"
+		offset = 1044K
+		partition-type-uuid = 2E54B353-1271-4842-806F-E436D6AF6985
+	}
+}