staging: most: core: separate property showing links

Currently an AIM has the following properties available to manage links:
  - write-only "remove_link" used to remove a link from a list
  - read/write "add_link" used to add a link to a list and display them

This patch transfers the read functionality of "add_link" to the new
read-only property "links" to build consistent set of properties to control
the list of links.
Signed-off-by: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/mostcore/core.c

@@ -831,9 +831,9 @@ static void most_aim_release(struct kobject *kobj)
 	kfree(aim_obj);
 }
 
-static ssize_t add_link_show(struct most_aim_obj *aim_obj,
-			     struct most_aim_attribute *attr,
-			     char *buf)
+static ssize_t links_show(struct most_aim_obj *aim_obj,
+			  struct most_aim_attribute *attr,
+			  char *buf)
 {
 	struct most_c_obj *c;
 	struct most_inst_obj *i;
@@ -854,6 +854,9 @@ static ssize_t add_link_show(struct most_aim_obj *aim_obj,
 	return offs;
 }
 
+static struct most_aim_attribute most_aim_attr_links =
+	__ATTR_RO(links);
+
 /**
  * split_string - parses and changes string in the buffer buf and
  * splits it into two mandatory and one optional substrings.
@@ -998,7 +1001,7 @@ static ssize_t add_link_store(struct most_aim_obj *aim_obj,
 }
 
 static struct most_aim_attribute most_aim_attr_add_link =
-	__ATTR_RW(add_link);
+	__ATTR_WO(add_link);
 
 /**
  * remove_link_store - store function for remove_link attribute
@@ -1044,6 +1047,7 @@ static struct most_aim_attribute most_aim_attr_remove_link =
 	__ATTR_WO(remove_link);
 
 static struct attribute *most_aim_def_attrs[] = {
+	&most_aim_attr_links.attr,
 	&most_aim_attr_add_link.attr,
 	&most_aim_attr_remove_link.attr,
 	NULL,