serial:ifx6x60:Delete SPI timer when shut down port

When shut down SPI port, it's possible that MRDY has been asserted and a SPI
timer was activated waiting for SRDY assert, in the case, it needs to delete
this timer.
Signed-off-by: NChen Jun <jun.d.chen@intel.com>
Signed-off-by: Nchanning <chao.bi@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/ifx6x60.c

@@ -637,6 +637,7 @@ static void ifx_port_shutdown(struct tty_port *port)
 
 	clear_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags);
 	mrdy_set_low(ifx_dev);
+	del_timer(&ifx_dev->spi_timer);
 	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
 	tasklet_kill(&ifx_dev->io_work_tasklet);
 }