msm: msm_bus: Optimize the bus commit path

Optimize the bus commit path. Currently the driver iterates over all
devices during the aggregation portion of the transaction which can
be expensive depending on the size of the bus topology. Modified the
bus driver to allow iterating over only those devices whose bus
parent was affected by the current transaction.
Also don't commit the bus and bandwidth requests for each path
separately, rather do this at the end so that the driver doesn't end
up sending duplicate requests for resources common to different paths.

Change-Id: I346fb13c741a1baeea19d442a9722f78f1afdd13
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>