i2c: Fix section mismatch

The function i2c_ssbi_probe is referenced outside of the __init section.
This is fixed by calling platform_driver_probe instead of
platform_driver_register since this device is not hotplugable.

Change-Id: I9f217ce230b52d2037a49ba49bc7342ceb076be5
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: nobodyAtall <tsogkas@ceid.upatras.gr>
Signed-off-by: garwedgess <garethwilliams21@gmail.com>