fs/ntfs3: In function ntfs_set_acl_ex do not change inode->i_mode if called from function ntfs_init_acl

ntfs_init_acl sets mode. ntfs_init_acl calls ntfs_set_acl_ex.
ntfs_set_acl_ex must not change this mode.
Fixes xfstest generic/444
Fixes: be71b5cb ("fs/ntfs3: Add attrib operations")
Reviewed-by: Joe Perches <joe@perches.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>