doc: README.commands: fix type

%s/commmand/command/

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.commands b/doc/README.commands
index 0ccadae..e03eb44 100644
--- a/doc/README.commands
+++ b/doc/README.commands
@@ -67,7 +67,7 @@
 Command function
 ----------------
 
-The commmand function pointer has to be of type
+The command function pointer has to be of type
 int (*cmd)(struct cmd_tbl_s *cmdtp, int flag, int argc, const char *argv[]);
 
 cmdtp:		Table entry describing the command (see above).