msm: vidc: Enable clocks before iommu attach

Change the fw load sequence to match the opposite of
unload sequence. This makes sure all clocks are on before calling
iommu attach.

Change-Id: Ib2b57ca656b50873282e2ef170b6ff693fe3ad5e
Signed-off-by: Shalaj Jain <shalajj@codeaurora.org>