msm: clock-8226: Add parent for a7 and a5 dedicated plls

Adding the parent more accurately describes the clock tree found in
hardware. This information is required for planned future updates, in
which parameters for the a7 and a5 pll are calculated dynamically.
Knowledge of the desired rate, and the parent's rate, is nessesary to
find these parameters.

Change-Id: Iea0f4bef9597b31d9f60b43103951524768e9ab8
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>