r8169: enforce RX_MULTI_EN for the 8168f.

Same narrative as eb2dc35d ("r8169: RxConfig
hack for the 8168evl.") regarding AMD IOMMU errors.

RTL_GIGA_MAC_VER_36 - 8168f as well - has not been reported to behave the
same.

Tested-by: David R <david@unsolicited.net>
Tested-by: Frédéric Leroy <fredo@starox.org>
Cc: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>