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/freescale/mx6ul_14x14_evk/README b/board/freescale/mx6ul_14x14_evk/README
index d48c7ba..1edccf6 100644
--- a/board/freescale/mx6ul_14x14_evk/README
+++ b/board/freescale/mx6ul_14x14_evk/README
@@ -1,7 +1,7 @@
-How to use U-boot on Freescale MX6UL 14x14 EVK
+How to use U-Boot on Freescale MX6UL 14x14 EVK
 -----------------------------------------------
 
-- Build U-boot for MX6UL 14x14 EVK:
+- Build U-Boot for MX6UL 14x14 EVK:
 
 $ make mrproper
 $ make mx6ul_14x14_evk_defconfig
@@ -28,5 +28,5 @@
 - Connect the USB cable between the EVK and the PC for the console.
 (The USB console connector is the one close the push buttons)
 
-- Insert the micro SD card in the board, power it up and U-boot messages should
+- Insert the micro SD card in the board, power it up and U-Boot messages should
 come up.