Input: wacom_i2c - fix compiler warning

Apparently GCC can't figure out that we bail if we fail to query device
and will not try to use 'features':

drivers/input/touchscreen/wacom_i2c.c: In function ‘wacom_i2c_probe’:
drivers/input/touchscreen/wacom_i2c.c:177:20: warning: ‘features.fw_version’
	may be used uninitialized in this function [-Wmaybe-uninitialized]
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/wacom_i2c.c

@@ -149,7 +149,7 @@ static int __devinit wacom_i2c_probe(struct i2c_client *client,
 {
 	struct wacom_i2c *wac_i2c;
 	struct input_dev *input;
-	struct wacom_features features;
+	struct wacom_features features = { 0 };
 	int error;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {