platform: msm: qcom-geni-se: Fix error during bus voting

During bus voting, a new vote is appended to the existing vote list.
If that list is empty, then it ends up accessing a garbage vote value.

Use the new bus vote value if the existing vote list is empty.

CRs-Fixed: 2093107
Change-Id: I9e351423b21c7edd24492ab27c18aefc9837dd29
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>