msm: mink: Convert Smcinvoke to platform driver

SMCInvoke driver has to support features that requires it to be a
platform driver instead of char/misc driver.

Adding support for platform driver.

Change-Id: I92ee434c0d610ed7ece2a49f5ef238da32af8792
Signed-off-by: Dinesh K Garg <dineshg@codeaurora.org>