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/include/kgdb.h b/include/kgdb.h
index b6ba742..616ce44 100644
--- a/include/kgdb.h
+++ b/include/kgdb.h
@@ -55,7 +55,7 @@
 extern void kgdb_putreg(struct pt_regs *, int, char *, int);
 extern void kgdb_putregs(struct pt_regs *, char *, int);
 extern int kgdb_trap(struct pt_regs *);
-extern void kgdb_breakpoint(int argc, char * const argv[]);
+void kgdb_breakpoint(int argc, char *const argv[]);
 
 /* these functions are provided by the platform serial driver */
 extern void kgdb_serial_init(void);