i2c: Make i2cdev_notifier_call static

The function i2cdev_notifier_call is used only in i2c-dev file
making it static.
Also removes the following sparse warning

drivers/i2c/i2c-dev.c:582:5: warning: symbol 'i2cdev_notifier_call'
was not declared. Should it be static?
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/i2c-dev.c

@@ -579,7 +579,7 @@ static int i2cdev_detach_adapter(struct device *dev, void *dummy)
 	return 0;
 }
 
-int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
+static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
 			 void *data)
 {
 	struct device *dev = data;