qseecom: Ensure CE clk is managed properly

clk access ref count is not updated correctly when issuing a
request that requires enabling clk. this results in leaving the
clk on during regular operation resulting in failure of the
device to go into low power mode.

Change-Id: I80232433ff09277fe83d78142dcec75e7493d96e
Signed-off-by: Zhen Kong <zkong@codeaurora.org>