Input: max8997_haptic - fix module alias

The driver is a platform driver and not a I2C driver so its modalias
should be exported with MODULE_DEVICE_TABLE(platform,...) instead of
MODULE_DEVICE_TABLE(i2c,...).

Also, remove the unnecessary MODULE_ALIAS("platform:max8997-haptic")
now that the correct module alias is created.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>