x86/platform/intel-mid: Enable GPIO expanders on Edison

x86/platform/intel-mid: Enable GPIO expanders on Edison

Intel Edison board provides GPIO expanders connected to I2C bus. Add necessary
file to get those enumerated.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dan O'Donovan <dan@emutex.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465984133-41639-1-git-send-email-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>