usb: gsi: Add debugfs support for remote wakeup on each interface

The new version of the compliance suite expects each
interface that advertises the remote wakeup capability
to generate a remote wakeup event in Superspeed mode.
The compliance suite ensures this by selectively
suspending each interface at a time and then expects
the interface to initiate a remote wakeup.
The current debugfs implementation though initiates
remote wakeup only on the first connected interface.

Hence change the implementation to initiate remote
wakeup by the interface which is selectively suspended
by the host in Superspeed mode. Whereas in Highspeed
mode initiate remote wakeup on the first connected
interface.

Change-Id: I45797e867aee17c5dcc592fe1e08b5a3943b4a8b
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>