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/mips/mach-ath79/ar934x/clk.c b/arch/mips/mach-ath79/ar934x/clk.c
index 09bdc25..5d0d455 100644
--- a/arch/mips/mach-ath79/ar934x/clk.c
+++ b/arch/mips/mach-ath79/ar934x/clk.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <clock_legacy.h>
+#include <command.h>
 #include <hang.h>
 #include <asm/io.h>
 #include <asm/addrspace.h>
@@ -319,7 +320,8 @@
 	return gd->mem_clk;
 }
 
-int do_ar934x_showclk(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+int do_ar934x_showclk(struct cmd_tbl *cmdtp, int flag, int argc,
+		      char *const argv[])
 {
 	ar934x_update_clock();
 	printf("CPU:       %8ld MHz\n", gd->cpu_clk / 1000000);