r8169: re-establish support for RTL8401 chip version

r8169 never had native support for the RTL8401, however it reportedly
worked with the fallback to RTL8101e [0]. Therefore let's add this
as an explicit assignment.

[0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=956868

Fixes: b4cc2dcc ("r8169: remove default chip versions")
Reported-by: NCamaleón <noelamac@gmail.com>
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/realtek/r8169_main.c

@@ -2127,6 +2127,8 @@ static enum mac_version rtl8169_get_mac_version(u16 xid, bool gmii)
 		{ 0x7cf, 0x348,	RTL_GIGA_MAC_VER_07 },
 		{ 0x7cf, 0x248,	RTL_GIGA_MAC_VER_07 },
 		{ 0x7cf, 0x340,	RTL_GIGA_MAC_VER_13 },
+		/* RTL8401, reportedly works if treated as RTL8101e */
+		{ 0x7cf, 0x240,	RTL_GIGA_MAC_VER_13 },
 		{ 0x7cf, 0x343,	RTL_GIGA_MAC_VER_10 },
 		{ 0x7cf, 0x342,	RTL_GIGA_MAC_VER_16 },
 		{ 0x7c8, 0x348,	RTL_GIGA_MAC_VER_09 },