tcmu: make array tcmu_attrib_attrs static const

The array tcmu_attrib_attrs does not need to be in global scope, so make
it static.

Cleans up sparse warning:
"symbol 'tcmu_attrib_attrs' was not declared. Should it be static?"
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_user.c

@@ -1672,7 +1672,7 @@ static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
 }
 CONFIGFS_ATTR(tcmu_, emulate_write_cache);
 
-struct configfs_attribute *tcmu_attrib_attrs[] = {
+static struct configfs_attribute *tcmu_attrib_attrs[] = {
 	&tcmu_attr_cmd_time_out,
 	&tcmu_attr_dev_path,
 	&tcmu_attr_dev_size,