qcom: clock-cpu-8994: Use scm_call to set the CCI divider as well

The CCI clock divider is also inaccessible to the non-secure
world in 8994 V1. Use the secure IO API to set and read it.

Change-Id: I3c31633fd89138ebba109956a3031107972e8acd
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>