ARM: dts: msm8916: Add prng clock controller device

Add prng clk controller device to the device tree. This will allow the
clock drivers to probe these devices and register the necessary clock
tables.

Change-Id: I425f27ec951376e7f1ab434870f2d2a3cc5e4c76
Signed-off-by: AnilKumar Chimata <anilc@codeaurora.org>