usb: gadget: Fix remote wakeup failure in Superspeed Plus

The speed checks in the code path to initiate remote wakeup
fails any remote wakeup requests by the function drivers
in Superspeed Plus mode and allows it only in Superspeed mode.
Hence fix this checks to support the remote wakeup capability
in Superspeed Plus mode as well.

Change-Id: Ieaa61325b2fc0006943506292a3819748fcc7600
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>