usb: gadget: MBIM function driver for QCOM chipsets

This driver implements Mobile Broadband Interface Model protocol.
Control messages are transferred through QBI module
running in user space and communicating with mbim
using file operations interface android_mbim.
Data is transferred on SPS, Bam-to-Bam.

Change-Id: Ifc4b3f7e21b1a0dac377af272f9ae922ec9c7e2e
Signed-off-by: Anna Perel <aperel@codeaurora.org>