clk: qcom: support Brammo type Alpha PLL

The Brammo type of Alpha PLL doesn't allow configuration of a
VCO, but it does support dynamic update in which the frequency
can be changed dynamically without turning off the PLL.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>