msm: board-krypton: add rpm controlled regulator support

Add a call to rpm_regulator_smd_driver_init() in the
msmkrypton_add_drivers() function so that the rpm regulator devices
are probed in the correct order (before other devices).

Change-Id: Icbc603fc53573526124fd9b8b49533ae3dacc439
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>