usb: gagdget: Fix handling of bus suspend/resume with MBIM and ECM

In HSUSB mode, host makes decision to enable/disable remote wakeup.
It is being handled by using remote_wakeup flag to make decision
how to handle bus suspsend/resume fuctionality at MBIM and ECM
function level. This change fixes the same by adding same approach
with dwc3 ep0 handling of remote wakeup feature.

In SSUSB mode, host doesn't use remote wakeup feature instead it
uses SET_FEATURE control request with value as FUNCTION_SUSPEND.
This change adds speed change to override remote_wakeup flag check
with MBIM and ECM functions.

Change-Id: I70aa94c546d229802fb1c3fad69fb4da24a46584
Signed-off-by: Mayank Rana <mrana@codeaurora.org>