This is last minute change which fixes problems in runtime on AXS10x board caused by some changes in NAND framework and tiny documentation improvement. Anyways NAND flash storage was never really used on the board for various reasons and now we decided to drop it for good. Note this change only touches 1 ARC board so that should be safe for others. As usual - build tested in TravisCI, see https://travis-ci.org/abrodkin/u-boot/builds/512041342