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/cmd/rng.c b/cmd/rng.c
index 76367fe..9747c11 100644
--- a/cmd/rng.c
+++ b/cmd/rng.c
@@ -11,7 +11,7 @@
 #include <malloc.h>
 #include <rng.h>
 
-static int do_rng(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
 	size_t n = 0x40;
 	struct udevice *dev;