NFC: Add support to get NFC interface type

Add new ioctl NFC_GET_PLATFORM_TYPE to get the NFC
interface type. This is used by the NFC HAL to 
do the firmware download according to the interface
type.

Change-Id: I45e8c4814e04348daa88c8b7a026bd44fa84163a
Signed-off-by: Karthik Poosa <kpoosa2@codeaurora.org>