mx23_olinuxino: Fix netboot console

The netargs variable was referencing the non-existing variable
console_mainline. Change that to console variable instead.
Signed-off-by: NAlexandre Pereira da Silva <aletes.xgr@gmail.com>
Acked-by: NOtavio Salvador <otavio@ossystems.com.br>

include/configs/mx23_olinuxino.h

@@ -227,7 +227,7 @@
 		"else " \
 			"bootm; " \
 		"fi;\0" \
-	"netargs=setenv bootargs console=${console_mainline},${baudrate} " \
+	"netargs=setenv bootargs console=${console},${baudrate} " \
 		"root=/dev/nfs " \
 		"ip=dhcp nfsroot=${serverip}:${nfsroot},v3,tcp\0" \
 	"netboot=echo Booting from net ...; " \