clk: qcom: clk-alpha-pll: Avoid reconfiguring Trion and Regera PLLs

Return early from the Trion and Regera PLL configure operations
if they've been configured already.

Change-Id: I6865571d5d54d548faa297360d65f49ca13a9f0f
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>