net: openvswitch: release vport resources on failure

A recent commit introducing upcall packet accounting failed to properly
release the vport object when the per-cpu stats struct couldn't be
allocated.  This can cause dangling pointers to dp objects long after
they've been released.

Cc: wangchuanlei <wangchuanlei@inspur.com>
Fixes: 1933ea36

 ("net: openvswitch: Add support to count upcall packets")
Reported-by:  <syzbot+8f4e2dcfcb3209ac35f9@syzkaller.appspotmail.com>
Signed-off-by: Aaron Conole <aconole@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://lore.kernel.org/r/20221220212717.526780-1-aconole@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>