clock-gcc-8916: Add null terminator to the of_device_id table

Add a null terminator to the of_device_id table to allow the
device tree framework to correctly parse the table and prevent
memory corruption.

Change-Id: I91ac9e48dafd14147a3f41d2a3804091365306b7
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>