usb: dwc2: make the scheduler handle excessive NAKs better

I'm seeing problems with a d-link dwcl-g122 wifi dongle that
someone sent me. There are reports of other wifi dongles with the
same/similar problem. The devices appear to be NAKing to the point
of confusing the dwc2 driver completely.

The attached patch helps with my d-link dwl-g122 - it's adapted
from the Raspberry Pi dwc_otg driver, which is a modified version
of the Synopsys vendor driver. The error recovery is still valid
after the patch, I think.

Cc: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Nick Hudson <skrll@netbsd.org>
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>