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/mpc8313erdb/README b/board/freescale/mpc8313erdb/README
index be7ef32..697cee4 100644
--- a/board/freescale/mpc8313erdb/README
+++ b/board/freescale/mpc8313erdb/README
@@ -70,7 +70,7 @@
 
 5.	Downloading and Flashing Images
 
-5.1	Reflash U-boot Image using U-boot
+5.1	Reflash U-Boot Image using U-Boot
 
 	NOR flash:
 
@@ -81,7 +81,7 @@
 	first, to make sure that the TFTP load will succeed before it
 	goes ahead and wipes out your current firmware.  And of course,
 	have an alternate means of programming the flash available
-	if the new u-boot doesn't boot.
+	if the new U-Boot doesn't boot.
 
 	NAND flash: