cmd: usb_mass_storage: show device interface name

Show the interface name (i.e. 'mmc') in the information string to ease
user checking which device is exported via USB Mass Storage protocol.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
diff --git a/cmd/usb_mass_storage.c b/cmd/usb_mass_storage.c
index cf2f559..14fa723 100644
--- a/cmd/usb_mass_storage.c
+++ b/cmd/usb_mass_storage.c
@@ -115,8 +115,8 @@
 		ums[ums_count].name = name;
 		ums[ums_count].block_dev = *block_dev;
 
-		printf("UMS: LUN %d, dev %d, hwpart %d, sector %#x, count %#x\n",
-		       ums_count, ums[ums_count].block_dev.devnum,
+		printf("UMS: LUN %d, dev %s %d, hwpart %d, sector %#x, count %#x\n",
+		       ums_count, devtype, ums[ums_count].block_dev.devnum,
 		       ums[ums_count].block_dev.hwpart,
 		       ums[ums_count].start_sector,
 		       ums[ums_count].num_sectors);