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/spear-common.h b/include/configs/spear-common.h
index d2630f4..a309448 100644
--- a/include/configs/spear-common.h
+++ b/include/configs/spear-common.h
@@ -12,7 +12,7 @@
  */
 
 
-/* U-boot Load Address */
+/* U-Boot Load Address */
 #define CONFIG_SYS_TEXT_BASE			0x00700000
 
 /* Ethernet driver configuration */