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/mediatek/mt7622/mt7622_rfb.c b/board/mediatek/mt7622/mt7622_rfb.c
index 912b993..6a5f936 100644
--- a/board/mediatek/mt7622/mt7622_rfb.c
+++ b/board/mediatek/mt7622/mt7622_rfb.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <config.h>
+#include <env.h>
 #include <init.h>
 
 DECLARE_GLOBAL_DATA_PTR;