cifs: address trivial coverity warning

This is not actually a bug but as Coverity points out we shouldn't
be doing an "|=" on a value which hasn't been set (although technically
it was memset to zero so isn't a bug) and so might as well change
"|=" to "=" in this line

Detected by CoverityScan, CID#728535 ("Unitialized scalar variable")
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

fs/cifs/inode.c

@@ -333,7 +333,7 @@ cifs_create_dfs_fattr(struct cifs_fattr *fattr, struct super_block *sb)
 	fattr->cf_mtime = timespec64_trunc(fattr->cf_mtime, sb->s_time_gran);
 	fattr->cf_atime = fattr->cf_ctime = fattr->cf_mtime;
 	fattr->cf_nlink = 2;
-	fattr->cf_flags |= CIFS_FATTR_DFS_REFERRAL;
+	fattr->cf_flags = CIFS_FATTR_DFS_REFERRAL;
 }
 
 static int