media: dvb_frontend: add proper __user annotations

Solves those warnings:
	drivers/media/dvb-core/dvb_frontend.c:2297:39: warning: incorrect type in argument 1 (different address spaces)
	drivers/media/dvb-core/dvb_frontend.c:2297:39:    expected void const [noderef] <asn:1>*<noident>
	drivers/media/dvb-core/dvb_frontend.c:2297:39:    got struct dtv_property *props
	drivers/media/dvb-core/dvb_frontend.c:2331:39: warning: incorrect type in argument 1 (different address spaces)
	drivers/media/dvb-core/dvb_frontend.c:2331:39:    expected void const [noderef] <asn:1>*<noident>
	drivers/media/dvb-core/dvb_frontend.c:2331:39:    got struct dtv_property *props

No functional changes.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-core/dvb_frontend.c

@@ -2294,7 +2294,7 @@ static int dvb_frontend_handle_ioctl(struct file *file,
 		if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
 			return -EINVAL;
 
-		tvp = memdup_user(tvps->props, tvps->num * sizeof(*tvp));
+		tvp = memdup_user((void __user *)tvps->props, tvps->num * sizeof(*tvp));
 		if (IS_ERR(tvp))
 			return PTR_ERR(tvp);
 
@@ -2328,7 +2328,7 @@ static int dvb_frontend_handle_ioctl(struct file *file,
 		if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
 			return -EINVAL;
 
-		tvp = memdup_user(tvps->props, tvps->num * sizeof(*tvp));
+		tvp = memdup_user((void __user *)tvps->props, tvps->num * sizeof(*tvp));
 		if (IS_ERR(tvp))
 			return PTR_ERR(tvp);