board: sl28: add network variant 2 support

Although this variant has two external network ports, they are not (yet)
supported by the bootloader because they are connected via an internal
network switch. Otherwise its the same as the other variants.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>

board/kontron/sl28/spl.c

@@ -19,6 +19,8 @@ int board_fit_config_name_match(const char *name)
 	switch (variant) {
 	case 1:
 		return strcmp(name, "fsl-ls1028a-kontron-sl28-var1");
+	case 2:
+		return strcmp(name, "fsl-ls1028a-kontron-sl28-var2");
 	case 3:
 		return strcmp(name, "fsl-ls1028a-kontron-sl28-var3");
 	case 4: