IB/ipoib: Remove IPOIB_MCAST_RUN bit

After Doug Ledford's changes there is no need in that bit, it's
semantic becomes subset of the IPOIB_FLAG_OPER_UP bit.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>