qseecom: update clock ref count when bus scaling timer is running

When there are multiple enable/dislable clock operations, ce clock
ref count is not updated correctly when the timer to disable clock
is running. Specifically, the ref count is not decreased when the
old operation is finished and then we reset clock for the new enable
clock. Thus, the ce clock is not disabled after all operation are
completed due to incorrect clk ref count. We make a change to
decrease clock reference count before reset timer, when the timer
is running, then clock is disabled when all ce clock operations
finish and the timer expires.

Change-Id: If71fd526acd9a74bf21731841fae0b98e76a89b5
Signed-off-by: Zhen Kong <zkong@codeaurora.org>