Don't throttle on -EILSEQ urb status if requested by a minidriver.
It seems the ueagle modems are buggy, giving -EILSEQ when they
have no data to send.  The ueagle change will be sent separately
by the ueagle guys.  Patch by Matthieu Castet.
Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>