Input: st1232 - rely on I2C core to configure wakeup interrupt

When I2C client is created with I2C_CLIENT_WAKE flag (which happens
either because we have "wakeup-source" device property or the flag
was passed in when creating an I2C client manually), I2C core will
take care of configuring interrupt as wakeup source on suspend.

Tested-by: Matthias Fend <Matthias.Fend@wolfvision.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>