global: Use proper project name U-Boot

Use proper project name in comments, Kconfig, readmes.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/0dbdf0432405c1c38ffca55703b6737a48219e79.1684307818.git.michal.simek@amd.com
diff --git a/doc/usage/dfu.rst b/doc/usage/dfu.rst
index ed47ff5..68cacbb 100644
--- a/doc/usage/dfu.rst
+++ b/doc/usage/dfu.rst
@@ -9,7 +9,7 @@
 The Device Firmware Upgrade (DFU) allows to download and upload firmware
 to/from U-Boot connected over USB.
 
-U-boot follows the Universal Serial Bus Device Class Specification for
+U-Boot follows the Universal Serial Bus Device Class Specification for
 Device Firmware Upgrade Version 1.1 the USB forum (DFU v1.1 in www.usb.org).
 
 U-Boot implements this DFU capability (CONFIG_DFU) with the command dfu