net/rocker: Plug memory leak in pci_rocker_init()

pci_rocker_init() leaks a World when the name more than 9 chars,
then return a negative value directly, doesn't make a correct
cleanup. So add a new goto label to fix it.

Cc: jasowang@redhat.com
Cc: jiri@resnulli.us
Cc: armbru@redhat.com
Cc: f4bug@amsat.org
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>