Input: Fix lm8323 probe and module unloading

Make module unloading and reloading behave:

- Driver probe could fail if input_register_device fails as
  no error was returned from probe

- Driver interrupt was using unused platform_data field,
  change to use i2c platform data interrupt instead

- Free resources on unloading module

- Mark platform data as __init_or_module

Signed-off-by: Tony Lindgren <tony@atomide.com>