GitLab

If one of the isochronous or the interrupt EP URB cannot be submitted,
we should clean-up properly and avoid hanging the dahdi_cfg process
at 100% CPU itilization in an un-killable state.

Closes: OS#5477 (https://osmocom.org/issues/5477)
Change-Id: Ie6f7f11a64fae0d8c2b7c8ae90df886f2eb8f0c2