doc: fix typo loady in loadb man-page

%s/loady/loadb/

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/usage/cmd/loadb.rst b/doc/usage/cmd/loadb.rst
index b37d1d7..0464b1f 100644
--- a/doc/usage/cmd/loadb.rst
+++ b/doc/usage/cmd/loadb.rst
@@ -13,7 +13,7 @@
 Description
 -----------
 
-The loady command is used to transfer a file to the device via the serial line
+The loadb command is used to transfer a file to the device via the serial line
 using the Kermit protocol.
 
 The number of transferred bytes is saved in environment variable filesize.