[media] v4l2-ctrl: move function prototypes from common.h to ctrls.h

For some unknown reason several control prototypes where in v4l2-common.c
instead of in v4l2-ctrls.h. Move them and document them.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index b7cd7a6..911f3e5 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -670,6 +670,31 @@
   */
 void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify, void *priv);
 
+/** v4l2_ctrl_get_name() - Get the name of the control
+ * @id:		The control ID.
+ *
+ * This function returns the name of the given control ID or NULL if it isn't
+ * a known control.
+ */
+const char *v4l2_ctrl_get_name(u32 id);
+
+/** v4l2_ctrl_get_menu() - Get the menu string array of the control
+ * @id:		The control ID.
+ *
+ * This function returns the NULL-terminated menu string array name of the
+ * given control ID or NULL if it isn't a known menu control.
+ */
+const char * const *v4l2_ctrl_get_menu(u32 id);
+
+/** v4l2_ctrl_get_int_menu() - Get the integer menu array of the control
+ * @id:		The control ID.
+ * @len:	The size of the integer array.
+ *
+ * This function returns the integer array of the given control ID or NULL if it
+ * if it isn't a known integer menu control.
+ */
+const s64 *v4l2_ctrl_get_int_menu(u32 id, u32 *len);
+
 /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
   * @ctrl:	The control.
   *