clk: qcom: Consolidate common probe code

Most of the probe code is the same between all the different
clock controllers. Consolidate the code into a common.c file.
This makes changes to the common probe parts easier and reduces
chances for bugs.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>