tg3: Fix flow control settings not propagated to hardware

In tg3_setup_copper_phy(), if autonegotiation is disabled, we need to
relink only if the speed or duplex does not match the configured
setting.  If flow control does not match, a relink is not necessary as
flow control is not a PHY setting.  Later on, we'll call
tg3_setup_flow_ctrl() to set up the MAC to the desired flow control
settings if we're in full duplex mode.

Signed-off-by: Nithin Nayak Sujir <nsujir@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>