r8169: don't advertise pause in jumbo mode

It has been reported [0] that using pause frames in jumbo mode impacts
performance. There's no available chip documentation, but vendor
drivers r8168 and r8125 don't advertise pause in jumbo mode. So let's
do the same, according to Roman it fixes the issue.

[0] https://bugzilla.kernel.org/show_bug.cgi?id=212617



Fixes: 9cf9b84c ("r8169: make use of phy_set_asym_pause")
Reported-by: Roman Mamedov <rm+bko@romanrm.net>
Tested-by: Roman Mamedov <rm+bko@romanrm.net>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>