command: Remove the cmd_tbl_t typedef

We should not use typedefs in U-Boot. They cannot be used as forward
declarations which means that header files must include the full header to
access them.

Drop the typedef and rename the struct to remove the _s suffix which is
now not useful.

This requires quite a few header-file additions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.standalone b/doc/README.standalone
index 28ebde1..874ca2f 100644
--- a/doc/README.standalone
+++ b/doc/README.standalone
@@ -40,7 +40,7 @@
    that returns the ABI version of the running U-Boot. I.e., a
    typical application startup may look like this:
 
-	int my_app (int argc, char * const argv[])
+	int my_app (int argc, char *const argv[])
 	{
 		app_startup (argv);
 		if (get_version () != XF_VERSION)