Change the name of function mode_to_acl to mode_to_cifs_acl.

Handle return code in functions mode_to_cifs_acl and
cifs_acl_to_fattr.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>