msm: kgsl: Change data type for GPU ib vote

Change data type for gpu ib vote to unsigned
long to suit the bw vote data type in devfreq
governor functions.

Change-Id: I6aeb201ee67d111ee527c17e051b5125968a9683
Signed-off-by: Archana Sriram <apsrir@codeaurora.org>
Signed-off-by: Pranav Patel <pranavp@codeaurora.org>