fs/cifs/smb2pdu.c: Make SMB2_notify_init static

Fix sparse warnings:

fs/cifs/smb2pdu.c:3200:1: warning: symbol 'SMB2_notify_init' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2pdu.c

@@ -3181,7 +3181,7 @@ SMB2_get_srv_num(const unsigned int xid, struct cifs_tcon *tcon,
  * See MS-SMB2 2.2.35 and 2.2.36
  */
 
-int
+static int
 SMB2_notify_init(const unsigned int xid, struct smb_rqst *rqst,
 		struct cifs_tcon *tcon, u64 persistent_fid, u64 volatile_fid,
 		u32 completion_filter, bool watch_tree)