mfd: max77686: Export OF module alias information

When the device is registered via OF, the OF table is used to match the
driver instead of the I2C device ID table but the entries in the latter
are used as aliasses to load the module if the driver was not built-in.

This is because the I2C core always reports an I2C module alias instead
of an OF one but that could change so it is better to always export it.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>