V4L/DVB (8757): v4l-dvb: fix a bunch of sparse warnings

Fixed a lot of sparse warnings: mostly warnings about shadowed variables
and signed/unsigned mismatches.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/dvb-usb/cxusb.c b/drivers/media/dvb/dvb-usb/cxusb.c
index aaa0b6f..5634002 100644
--- a/drivers/media/dvb/dvb-usb/cxusb.c
+++ b/drivers/media/dvb/dvb-usb/cxusb.c
@@ -210,7 +210,7 @@
 	if (d->state == DVB_USB_STATE_INIT &&
 	    usb_set_interface(d->udev, 0, 0) < 0)
 		err("set interface failed");
-	do; while (!(ret = cxusb_ctrl_msg(d, CMD_POWER_ON, NULL, 0, NULL, 0)) &&
+	do {} while (!(ret = cxusb_ctrl_msg(d, CMD_POWER_ON, NULL, 0, NULL, 0)) &&
 		   !(ret = cxusb_ctrl_msg(d, 0x15, NULL, 0, NULL, 0)) &&
 		   !(ret = cxusb_ctrl_msg(d, 0x17, NULL, 0, NULL, 0)) && 0);
 	if (!ret) {