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/board/sifive/fu540/fu540.c b/board/sifive/fu540/fu540.c
index e9d1cf9..d2a1ed0 100644
--- a/board/sifive/fu540/fu540.c
+++ b/board/sifive/fu540/fu540.c
@@ -8,6 +8,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <env.h>
 #include <init.h>
 #include <linux/delay.h>
 #include <linux/io.h>