Input: adp5588-keys - remove incorrect modalias

For i2c drivers, we should use "i2c:" prefix for modalias.

MODULE_DEVICE_TABLE will setup the modulalias for us, thus adding
a MODULE_ALIAS is redundant (in addition to being incorrect).

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>