move CLI prototypes to cli.h and add comments

Move the CLI prototypes from common.h to cli.h as part of an effort to
reduce the size of common.h.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/ait/cam_enc_4xx/cam_enc_4xx.c b/board/ait/cam_enc_4xx/cam_enc_4xx.c
index b5cc3ed..7c26ba0 100644
--- a/board/ait/cam_enc_4xx/cam_enc_4xx.c
+++ b/board/ait/cam_enc_4xx/cam_enc_4xx.c
@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <cli.h>
 #include <errno.h>
 #include <linux/mtd/nand.h>
 #include <nand.h>
diff --git a/board/amcc/yucca/cmd_yucca.c b/board/amcc/yucca/cmd_yucca.c
index dc78b73..3257c29 100644
--- a/board/amcc/yucca/cmd_yucca.c
+++ b/board/amcc/yucca/cmd_yucca.c
@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <cli.h>
 #include <command.h>
 #include "yucca.h"
 #include <i2c.h>
diff --git a/board/eltec/elppc/misc.c b/board/eltec/elppc/misc.c
index d80eaba..70d1f9a 100644
--- a/board/eltec/elppc/misc.c
+++ b/board/eltec/elppc/misc.c
@@ -7,6 +7,7 @@
 
 /* includes */
 #include <common.h>
+#include <cli.h>
 #include <linux/ctype.h>
 #include <pci.h>
 #include <net.h>
diff --git a/board/eltec/mhpc/mhpc.c b/board/eltec/mhpc/mhpc.c
index f3f564f..ff9e0ab 100644
--- a/board/eltec/mhpc/mhpc.c
+++ b/board/eltec/mhpc/mhpc.c
@@ -14,6 +14,7 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <cli.h>
 #include <linux/ctype.h>
 #include <commproc.h>
 #include "mpc8xx.h"
diff --git a/board/hymod/hymod.c b/board/hymod/hymod.c
index 5fec914..ea49e26 100644
--- a/board/hymod/hymod.c
+++ b/board/hymod/hymod.c
@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <cli.h>
 #include <mpc8260.h>
 #include <mpc8260_irq.h>
 #include <ioports.h>
diff --git a/board/hymod/input.c b/board/hymod/input.c
index 184902c..23d3f19 100644
--- a/board/hymod/input.c
+++ b/board/hymod/input.c
@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <cli.h>
 
 int
 hymod_get_serno (const char *prompt)