usb: host: ehci-msm2: Add bus voting support to driver

The controller driver may need to update MSM BUS client parameters
in order to vote for required bandwidth guarantees from the bus
(NOC, fabric, memory, etc.). Add support for msm_bus voting to
the driver. The specific parameters can be specified in device tree.

Change-Id: Ide84d28f95e23e77a6091f6a749796295d4ffa80
Signed-off-by: Jack Pham <jackp@codeaurora.org>