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/freescale/imxrt1020-evk/imxrt1020-evk.c b/board/freescale/imxrt1020-evk/imxrt1020-evk.c
index 06ad524..08f6ca9 100644
--- a/board/freescale/imxrt1020-evk/imxrt1020-evk.c
+++ b/board/freescale/imxrt1020-evk/imxrt1020-evk.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <init.h>
 #include <ram.h>
 #include <spl.h>
 #include <asm/io.h>