riscv: enable booting HiFive Unmatched from SATA

On the HiFive Unmatched a PCI to SATA adapter may be used to install a SATA
drive. Enable booting from it.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
diff --git a/include/configs/sifive-unmatched.h b/include/configs/sifive-unmatched.h
index d63a5f6..bea0eeb 100644
--- a/include/configs/sifive-unmatched.h
+++ b/include/configs/sifive-unmatched.h
@@ -40,6 +40,8 @@
 
 #define CONFIG_SYS_CACHELINE_SIZE	64
 
+#define CONFIG_SYS_SCSI_MAX_SCSI_ID	4
+
 /* Environment options */
 
 #ifndef CONFIG_SPL_BUILD
@@ -47,6 +49,7 @@
 	func(NVME, nvme, 0) \
 	func(USB, usb, 0) \
 	func(MMC, mmc, 0) \
+	func(SCSI, scsi, 0) \
 	func(PXE, pxe, na) \
 	func(DHCP, dhcp, na)