netlabel: Correct function name netlbl_mgmt_add() in the kerneldoc comments

Fix the following W=1 kernel build warning(s):

net/netlabel/netlabel_mgmt.c:78: warning: expecting prototype for netlbl_mgmt_add(). Prototype was for netlbl_mgmt_add_common() instead

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Xiongfeng Wang <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/netlabel/netlabel_mgmt.c

···
  */
 
 /**
- * netlbl_mgmt_add - Handle an ADD message
+ * netlbl_mgmt_add_common - Handle an ADD message
  * @info: the Generic NETLINK info block
  * @audit_info: NetLabel audit information
  *