Use correct spelling of "U-Boot"

Correct spelling of "U-Boot" shall be used in all written text
(documentation, comments in source files etc.).

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/board/bf525-ucr2/bf525-ucr2.c b/board/bf525-ucr2/bf525-ucr2.c
index 3e6df1f..36a725c 100644
--- a/board/bf525-ucr2/bf525-ucr2.c
+++ b/board/bf525-ucr2/bf525-ucr2.c
@@ -1,4 +1,4 @@
-/* U-boot - bf525-ucr2.c  board specific routines
+/* U-Boot - bf525-ucr2.c  board specific routines
  *
  * (C) Copyright 2000-2004
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.