The original change fixed an issue on RTL8168b by mimicking the vendor
driver behavior to disable MSI on chip versions before RTL8168d.
This however now caused an issue on a system with RTL8168c, see [0].
Therefore leave MSI disabled on RTL8168b, but re-enable it on RTL8168c.

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1792839

Fixes: 003bd5b4 ("r8169: don't use MSI before RTL8168d")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>