Merge pull request #574 from winfeng/patch-1

[bsp] Update uart.c in lpc176x bsp.

bsp/lpc176x/drivers/uart.c

@@ -89,6 +89,9 @@ void UART0_IRQHandler(void)
 
             uart->parent.rx_indicate(&uart->parent, length);
 		}
+	}else if(iir == IIR_RLS)
+	{
+		iir = LPC_Uart->LSR;	//oe pe fe oe read for clear interrupt	
 	}
 
 	return;