clk: qcom: clk-cpu-osm: Update the cycle counter calculation logic

When per core DCVS is disabled, then only core0's copy is used as
a proxy for the whole cluster. Update the cycle counter logic to
consider that.

Change-Id: Ic9b834d6e25dbb777916fe91d799c950be8e5f58
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>