[PATCH] USB: free allocated memory on io_edgeport startup memory failure

While an Edgeport is allocating individual port structures, if kmalloc
returns NULL, the serial structure is freed and -ENOMEM, but the ports
allocated before the failure are not freed.  This patch addresses that
condition.

Signed-off-by: Christopher Lund <docmax@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>