msm: vidc: Fix corruption in bus vote

msm_comm_vote_bus() calculates and prepares core->vote_data
structure under core->lock for all instances and sets the
prepared vote_data to hfi layer after releasing core->lock.
There is a possibility that this prepared vote_data can be
corrupted while hfi layer accessesing it if msm_comm_vote_bus()
is called by another instance in parallel. Fix the issue
by allocating a new vote_data structure for every call to
msm_comm_vote_bus() function.

Change-Id: I502027054d994ee8144a8505c47954a1f1e06be4
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>