r8169: fix jumbo packet handling on RTL8168e

r8169: fix jumbo packet handling on RTL8168e

Josef reported [0] that using jumbo packets fails on RTL8168e.
Aligning the values for register MaxTxPacketSize with the
vendor driver fixes the problem.

[0] https://bugzilla.kernel.org/show_bug.cgi?id=211827

Fixes: 7e4c8d0e4194 ("r8169: jumbo fixes.")
Reported-by: Josef Oškera <joskera@redhat.com>
Tested-by: Josef Oškera <joskera@redhat.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/b15ddef7-0d50-4320-18f4-6a3f86fbfd3e@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>