r8169: fix r8168fp_adjust_ocp_cmd function

The (0xBAF70000 & 0x00FFF000) << 6 should be (0xf70 << 18).

Fixes: 561535b0

 ("r8169: fix OCP access on RTL8117")
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Acked-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>