msm: clk: qcom: re-program PLL registers to power-on-reset value

Make sure to re-program the PLL registers to the
power-on-reset value before starting to program the PLL again
to ensure that it locks reliably.

Change-Id: I8d99d2bcff1a90b33c008ec3e492788bfe19fa37
Signed-off-by: Vara Reddy <varar@codeaurora.org>