media: usb: gspca: add a missed return-value check for do_command

do_command() may fail. The fix adds the missed return value of
do_command(). If it fails, returns its error code.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/usb/gspca/cpia1.c

@@ -547,10 +547,14 @@ static int do_command(struct gspca_dev *gspca_dev, u16 command,
 		}
 		if (sd->params.qx3.button) {
 			/* button pressed - unlock the latch */
-			do_command(gspca_dev, CPIA_COMMAND_WriteMCPort,
+			ret = do_command(gspca_dev, CPIA_COMMAND_WriteMCPort,
 				   3, 0xdf, 0xdf, 0);
-			do_command(gspca_dev, CPIA_COMMAND_WriteMCPort,
+			if (ret)
+				return ret;
+			ret = do_command(gspca_dev, CPIA_COMMAND_WriteMCPort,
 				   3, 0xff, 0xff, 0);
+			if (ret)
+				return ret;
 		}
 
 		/* test whether microscope is cradled */