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/include/configs/bf525-ucr2.h b/include/configs/bf525-ucr2.h
index d12963a..5a6067e 100644
--- a/include/configs/bf525-ucr2.h
+++ b/include/configs/bf525-ucr2.h
@@ -1,5 +1,5 @@
 /*
- * U-boot - Configuration file for bf525-ucr2 board
+ * U-Boot - Configuration file for bf525-ucr2 board
  * The board includes ADSP-BF525 rev. 0.2,
  * 32-bit SDRAM (SAMSUNG K4S561632H-UC75),
  * USB 2.0 High Speed OTG USB WIFI,