eth: fec: Fix lost promiscuous mode after reconnecting cable

If the Freescale fec is in promiscuous mode and network cable is
reconnected then the promiscuous mode get lost. The problem is caused
by a too soon call of set_multicast_list to re-enable promisc mode.
The FEC_R_CNTRL register changes are overwritten by fec_restart.

This patch fixes this by moving the call behind the init of FEC_R_CNTRL
register in fec_restart.

Successful tested on a i.MX28 board.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: David S. Miller <davem@davemloft.net>