usb: gadget: Add remote wakeup support to f_qc_ecm

On USB suspend, f_qc_ecm will register for BAM wakeup notification.
Upon wakeup event from the BAM, the u_bam_data will trigger a USB
remote wakeup.

Change-Id: I8a12030a9b9e5aeb584617280341ab4a6170adcb
Signed-off-by: Lena Salman <esalman@codeaurora.org>
Signed-off-by: Amit Blay <ablay@codeaurora.org>