[media] gspca - main: Handle the xHCI error on usb_set_interface()

This patch is adapted from a patch from Sarah Sharp (2010/05/03).
The xHCD handler checks the USB bandwidth on usb_set_interface()
instead of on usb_submit_urb().
Now, the same treatment is applied in case of error of both functions.

Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>