[media] tc90522: declare tc90522_functionality as static

drivers/media/dvb-frontends/tc90522.c:706:5: warning: symbol 'tc90522_functionality' was not declared. Should it be static?
drivers/media/dvb-frontends/tc90522.c:706:5: warning: no previous prototype for 'tc90522_functionality' [-Wmissing-prototypes]
 u32 tc90522_functionality(struct i2c_adapter *adap)
     ^

Cc: Akihiro Tsukada <tskd08@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/dvb-frontends/tc90522.c

@@ -703,7 +703,7 @@ tc90522_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 	return (ret == j) ? num : ret;
 }
 
-u32 tc90522_functionality(struct i2c_adapter *adap)
+static u32 tc90522_functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C;
 }