gpio: max732x: Drop unused support for irq and setup code via platform data

The only user of max732x_platform_data is arch/arm/mach-pxa/littleton.c
and it only uses .gpio_base. So drop the other members from the data struct
and simplify the driver accordingly.

The motivating side effect of this change is that the .remove() callback
cannot return a nonzero error code any more which prepares making i2c
remove callbacks return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

include/linux/platform_data/max732x.h

@@ -7,17 +7,5 @@
 struct max732x_platform_data {
 	/* number of the first GPIO */
 	unsigned	gpio_base;
-
-	/* interrupt base */
-	int		irq_base;
-
-	void		*context;	/* param to setup/teardown */
-
-	int		(*setup)(struct i2c_client *client,
-				unsigned gpio, unsigned ngpio,
-				void *context);
-	int		(*teardown)(struct i2c_client *client,
-				unsigned gpio, unsigned ngpio,
-				void *context);
 };
 #endif /* __LINUX_I2C_MAX732X_H */