msm: clock-samarium: Enable set rate for venus0_ocmemnoc_clk

Setting rate on ocmemnoc_clk_src is no longer handled by bus driver.
Enable Venus driver to call clk_set_rate on this clock to simply
its driver.

Change-Id: I88f091025f1f7422780c96ac8f621a4c256b7ca0
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>