efi: devicepath: add support for mbr partition.

Add support for mbr partition for loading barebox from usb key
or even from qemu fat partition as an efi payload.

Signed-off-by: Chali Anis <chalianis1@gmail.com>

Author: anischali

efi/devicepath.c

@@ -802,7 +802,8 @@ char *device_path_to_partuuid(const struct efi_device_path *dev_path)
 		struct efi_device_path_hard_drive_path *hd =
 			(struct efi_device_path_hard_drive_path *)dev_path;
 
-		if (hd->signature_type != SIGNATURE_TYPE_GUID)
+		if (hd->signature_type != SIGNATURE_TYPE_GUID &&
+			hd->signature_type != SIGNATURE_TYPE_MBR)
 			continue;
 
 		return xasprintf("%pUl", (efi_guid_t *)&(hd->signature[0]));