usb: gadget: ci13xxx_msm: Allow BAM enable and disable

There are scenarios where the USB BAM has to be reset.
For example, when the peer BAM is being reset, the USB BAM
must be reset as well, otherwise the BAM-BAM connection will
go out of sync.

In order to reset the USB BAM, the USB controller has to disable
the BAM first. After the USB BAM reset is completed, the USB
controller has to re-enable the USB BAM.

So this change adds the support for USB BAM enable/disable.
This is done by adding an API to ci13xxx_msm. A function driver can
ask for BAM enable/disable by calling this API.

This change doesn't add the support for the USB BAM reset sequence.

CRs-Fixed: 424867
Change-Id: Ib5518fafe3765f86bb09d1ce10723ec733543b35
Signed-off-by: Amit Blay <ablay@codeaurora.org>

Conflicts:
	include/linux/usb/msm_hsusb.h