As we currently need to support a mix of legacy platform data and
device tree intialized data, let's make sure things keep working
for the TWL GPIOs.

Mostly the issue is caused by the fact that DSS does not yet have
device tree bindings, so we need to rely on the TWL GPIO callback
for setting up things like LCD backlight for some boards.

As of_platform_populate() for the TWL GPIO is called by twl-core
after the I2C bus has been initialized, we cannot pass the auxdata
table from the board init code to twl-core like we used to with
just legacy platform data.

So let's use the omap_device bus hook to patch in the platform
data for TWL GPIO until we have sorted out the issues with the
TWL GPIOs and device tree bindings.

The other option was be to initialize twl core using legacy
platform data, which seems like a step backwards as we're moving
to device tree only initialization.  And we really don't want to
add custom configuration functions to the TWL GPIO driver either
for this.
Signed-off-by: Tony Lindgren <tony@atomide.com>