clk: msm: clock-gcc-californium: Add a7pll clock for cpuss

The a7pll clock can be used as a parent for the cpu clock.
Add a device tree entry for the same and enable it.

Change-Id: I9950d699270e88c44a96ccb3a8f86484e5d34b13
Signed-off-by: Devesh Jhunjhunwala <deveshj@codeaurora.org>