net: ti cpsw ethernet: set IFCTL_A bit in MACCONTROL

For RMII/RGMII mode operation in 100Mbps, the CPSW needs to set the
IFCTL_A bits in the MACCONTROL register. For all other PHY modes, this
bit is unused, so setting it unconditionally shouldn't cause any
trouble.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>