r8169: fix rtl_hw_jumbo_disable for RTL8168evl

r8169: fix rtl_hw_jumbo_disable for RTL8168evl

BugLink: https://bugs.launchpad.net/bugs/1858424
[ Upstream commit 0fc75219fe9a3c90631453e9870e4f6d956f0ebc ]

In referenced fix we removed the RTL8168e-specific jumbo config for
RTL8168evl in rtl_hw_jumbo_enable(). We have to do the same in
rtl_hw_jumbo_disable().

v2: fix referenced commit id

Fixes: 14012c9f3bb9 ("r8169: fix jumbo configuration for RTL8168evl")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>