cifs: Handle extended attribute name cifs_acl to generate cifs acl blob (try #4)

Add extended attribute name system.cifs_acl

Get/generate cifs/ntfs acl blob and hand over to the invoker however
it wants to parse/process it under experimental configurable option CIFS_ACL.

Do not get CIFS/NTFS ACL for xattr for attribute system.posix_acl_access

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsacl.c

@@ -608,7 +608,7 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
 }
 
 /* Retrieve an ACL from the server */
-static struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
+struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
 				      struct inode *inode, const char *path,
 				      u32 *pacllen)
 {