usb: gadget: f_sourcesink: Fix isoc transfer for USB_SPEED_SUPER_PLUS

Currently when gadget enumerates in super speed plus, the isoc
endpoint request buffer size is not calculated correctly. Fix
this by checking the gadget speed against USB_SPEED_SUPER_PLUS
and update the request buffer size.

Fixes: 90c4d057 ("usb: fix various gadgets null ptr deref on 10gbps cabling.")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Pavankumar Kondeti <quic_pkondeti@quicinc.com>
Link: https://lore.kernel.org/r/1642820602-20619-1-git-send-email-quic_pkondeti@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>