Correct spelling of "U-Boot" shall be used in all written text
(documentation, comments in source files etc.).
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NHeiko Schocher <hs@denx.de>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NMinkyu Kang <mk7.kang@samsung.com>