msm: msm_bus: Shrink number of batches sent to Rpmh

Rather than batching BCM requests based on VCD, reduce
the number of batches by fitting the highest amount of
requests per batch without ungrouping the requests from
the same VCD. This should help to reduce congestion
from clients requests that span multiple VCDs and
help maintain priority within one batch.

Change-Id: Ie84458f8846772848e6d7f3f60cbc0e0cd3eaa65
Signed-off-by: David Dai <daidavid1@codeaurora.org>