dwc3: Add usb_get_remote_wakeup_status() API()

USB composite device updates to host about its wakeup capability
using bmAttribute, and USB host may support remote wakeup
functionality using SET_FEATURE. UDC gadget ops supports wakeup()
API which can be invoked by USB function driver to resume USB bus
by signaling remote wakeup. With HW accelerated path IPA will need
to know if host has enabled remote wakeup in order to decide whether
to suspend or disconnect the GSI channels. Add an API to allow USB
GSI driver to query the current remote wakeup enabled status.

Change-Id: I09eb62714f9df90d68cce5c478dc19096477709e
Signed-off-by: Mayank Rana <mrana@codeaurora.org>