[ARM] Make the assabet machine always use the same uart mapping.

Traditionally, the Assabet reverses its mapping of UART1 and UART3
when the Neponset board is connected.  This can be (a) confusing
and (b) annoying when the boot loader uses UART1.  We therefore
have a fixed mapping between the ttySA names and the physical
UARTs on this platform.

arch/arm/mach-sa1100/assabet.c

@@ -302,21 +302,24 @@ static void __init assabet_map_io(void)
 		 */
 		neponset_map_io();
 #endif
+	} else {
+		sa1100_register_uart_fns(&assabet_port_fns);
+	}
+
 	/*
 	 * When Neponset is attached, the first UART should be
 	 * UART3.  That's what Angel is doing and many documents
 	 * are stating this.
+	 *
 	 * We do the Neponset mapping even if Neponset support
 	 * isn't compiled in so the user will still get something on
 	 * the expected physical serial port.
+	 *
+	 * We no longer do this; not all boot loaders support it,
+	 * and UART3 appears to be somewhat unreliable with blob.
 	 */
-		sa1100_register_uart(0, 3);
-		sa1100_register_uart(2, 1);
-	} else {
-		sa1100_register_uart_fns(&assabet_port_fns);
-		sa1100_register_uart(0, 1);	/* com port */
-		sa1100_register_uart(2, 3);	/* radio module */
-	}
+	sa1100_register_uart(0, 1);
+	sa1100_register_uart(2, 3);
 }