iommu: msm: Add support for additional custom clk

Some IOMMU's need an additional clock to be turned on to allow
access to IOMMU registers. This clock is not part of the general
clock controller registers and thus a regular clock api does not
exist for this clock.

Also add custom clock for Venus IOMMU.

Change-Id: I73b3ae4989e7c9e72c6822d441aa32c33e53c44c
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
5 files changed