usb: f_gsi: Report Function Remote Wake capabilities

Add support for sending Function Wake capabilities in
response to GET_STATUS from the host. GET_STATUS addressed
to an Interface allows the device to report if it is capable
of doing a Function Remote Wake. Windows8 MBIM hosts request this
information before enabling Suspend in SS mode.

CRs-Fixed: 966352
Change-Id: Ic73ab794b6b3e70733c0362785ec601c6610a3e6
Signed-off-by: Devdutt Patnaik <dpatnaik@codeaurora.org>