When shutting down the UART, clear the interrupt status register. Bits
in the ISR are cleared by writing them as '1'.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Reviewed-by: NMoritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>