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/arch/sh/lib/zimageboot.c b/arch/sh/lib/zimageboot.c
index 602776a..c38f093 100644
--- a/arch/sh/lib/zimageboot.c
+++ b/arch/sh/lib/zimageboot.c
@@ -10,11 +10,14 @@
  */
 
 #include <common.h>
+#include <command.h>
+#include <env.h>
 #include <irq_func.h>
 #include <asm/io.h>
 #include <asm/zimage.h>
 
-int do_sh_zimageboot (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+int do_sh_zimageboot(struct cmd_tbl *cmdtp, int flag, int argc,
+		     char *const argv[])
 {
 	ulong (*zboot_entry)(int, char * const []) = NULL;
 	char *s0, *s1;