dm: scsi: Add a device pointer to scan_exec(), scsi_bus_reset()

With driver model these functions need a device pointer. Add one even
when CONFIG_DM_SCSI is not defined. This avoids having ugly conditional
function prototypes, When CONFIG_DM_SCSI is not defined we can just ignore
the pointer.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/cmd/scsi.c b/cmd/scsi.c
index 4213ec8..46171e5 100644
--- a/cmd/scsi.c
+++ b/cmd/scsi.c
@@ -36,7 +36,7 @@
 	case 2:
 		if (strncmp(argv[1], "res", 3) == 0) {
 			printf("\nReset SCSI\n");
-			scsi_bus_reset();
+			scsi_bus_reset(NULL);
 			ret = scsi_scan(1);
 			if (ret)
 				return CMD_RET_FAILURE;