mfd: Move twl-core device_init_wakeup to after platform_device_add

device_init_wakeup uses the dev_name() of the device to set the
name of the wakeup_source which appears in
/sys/kernel/debug/wakeup_sources.

For a platform device, that name is not set until platform_device_add
calls dev_set_name.

So the call to device_init_wakeup() must be after the call to
platform_device_add().
Making this change causes correct names to appear in the
wakeup_sources file.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>