msm: pil-venus: Add bus bandwidth proxy vote and unvote

mmss_s0_axi_clk and mmss_mmssnoc_axi_clk need to be on for venus
access ddr. Therefore, add the proxy vote for the bus bandwidth
from venus to ddr to make sure after venus can access ddr after
being brought out of reset.

Also, need to unvote the bus bandwidth later so that the venus
take full control of bus bandwidth vote.

Change-Id: I9de067a13c394c1d78c69bec309c81b47d64b69f
Signed-off-by: Tianyi Gou <tgou@codeaurora.org>