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/drivers/scsi/sandbox_scsi.c b/drivers/scsi/sandbox_scsi.c
index d943d1f..ac60ae0 100644
--- a/drivers/scsi/sandbox_scsi.c
+++ b/drivers/scsi/sandbox_scsi.c
@@ -11,15 +11,16 @@
 #include <common.h>
 #include <scsi.h>
 
-void scsi_bus_reset(void)
+int scsi_bus_reset(struct udevice *dev)
 {
+	return 0;
 }
 
 void scsi_init(void)
 {
 }
 
-int scsi_exec(struct scsi_cmd *pccb)
+int scsi_exec(struct udevice *dev, struct scsi_cmd *pccb)
 {
 	return 0;
 }