clk: qcom: clk-cpu-osm: Rework CPU and L3 clocks enable logic

(1) The qcom-cpufreq driver relies on the OSM driver to place proxy
votes on the CPU core clocks. In the case where per-core DCVS is
not enabled, in order for that dependency to work, the OSM driver
should place all its proxy votes for a given cluster on its first
core. Add support for that.
(2) Enable OSM for the L3 clock domain prior to doing so for the
other CPU clock domains.

Change-Id: I11e2c73c29ca497ab5783f91d9ae9d4fdf3b2104
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>