USB: ehci-dbgp: drop dead code.

We can only reach this spot by breaking out of the scan loop,
so by construction ret > 0.

Found by Coverity, in a copy of this file in the Xen sources.

Signed-off-by: Tim Deegan <tim@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>