usb: dwc3: Add QTI MSM platform specific feature and other changes

This change adds the following QTI MSM platform specific features
to the USB DWC3 core & gadget drivers:
  - BAM/DBM endpoint support
  - GSI endpoint support
  - low power mode
  - glue layer notifications
  - high speed-only fallback
  - additional debug logging

Change-Id: I0f733d05f3f88a4a734d8489b5eb548391ab3af3
Signed-off-by: Jack Pham <jackp@codeaurora.org>