clk: qcom: Reconfigure alpha PLL during set_rate

During set_rate read the L value to determine
if the configuration is required again, otherwise the
PLL would fail to lock or enable due to lost/missing
values.

Change-Id: If4753cfe0e4491a33820d1a77530c884c7006ac4
Signed-off-by: Veera Vegivada <vvegivad@codeaurora.org>