V4L/DVB (6070): Fix a warning at dvb_net

static function dvb_net_sec declares input arg "pkt" as u8. However, the
same argument at dvb_net_sec_callback is defined as "const u8". When
calling dvb_net_sec, this is casted as just "u8".

gcc 4.2.1 generates a warning about that:

  CC [M]  drivers/media/dvb/dvb-core/dvb_net.o
drivers/media/dvb/dvb-core/dvb_net.c: In function "dvb_net_sec_callback":
drivers/media/dvb/dvb-core/dvb_net.c:905: warning: passing argument 2 of
		"dvb_net_sec" discards qualifiers from pointer target type
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/dvb-core/dvb_net.c

@@ -800,7 +800,8 @@ static int dvb_net_ts_callback(const u8 *buffer1, size_t buffer1_len,
 }
 
 
-static void dvb_net_sec(struct net_device *dev, u8 *pkt, int pkt_len)
+static void dvb_net_sec(struct net_device *dev, const u8 *pkt, int
+pkt_len)
 {
 	u8 *eth;
 	struct sk_buff *skb;
@@ -902,7 +903,7 @@ static int dvb_net_sec_callback(const u8 *buffer1, size_t buffer1_len,
 	 * we rely on the DVB API definition where exactly one complete
 	 * section is delivered in buffer1
 	 */
-	dvb_net_sec (dev, (u8*) buffer1, buffer1_len);
+	dvb_net_sec (dev, buffer1, buffer1_len);
 	return 0;
 }