nitrogen6x: config: add initrd_high

Support RAM disks by setting initrd_high. See commit 7e9603e

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>

include/configs/nitrogen6x.h

@@ -282,6 +282,7 @@
 		"echo ; echo serial console at 115200, 8N1 ; echo ; " \
 		"echo details at http://boundarydevices.com/6q_bootscript ; " \
 		"setenv stdout serial\0" \
+	"initrd_high=0xffffffff\0" \
 	"upgradeu=for dtype in ${bootdevs}" \
 		"; do " \
 		"for disk in 0 1 ; do ${dtype} dev ${disk} ;" \