[OE-core] Yocto Bug#10456 discuss

[Dengke Du]

Hi Jussi and bruce

Yocto Bug#10456: X can not launch on qemumips64

I find the kernel 4.4 is ok, and on the latest 4.9 is ok, but on kernel 
4.8 is failed.

This is because this commit in linux-yocto-4.8:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

commit d03516df837587368fc6e75591f6329c072b9eb5
Author: Matthew Leach <matthew.leach at codethink.co.uk>
Date:   Tue Jun 21 16:19:49 2016 +0100

     tty: serial: 8250: add CON_CONSDEV to flags

     When using the 8250 as a boot console and the main console results in
     messages being printed twice.  The console framework will only
     unregister boot consoles if a new console is registered with the
     CON_CONSDEV flag set.

     Set this flag for the univ8250 console to prevent double-registration.

     Signed-off-by: Matthew Leach <matthew.leach at codethink.co.uk>
     Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index fa823a5..dcf43f6 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -675,7 +675,7 @@ static struct console univ8250_console = {
         .device         = uart_console_device,
         .setup          = univ8250_console_setup,
         .match          = univ8250_console_match,
-       .flags          = CON_PRINTBUFFER | CON_ANYTIME,
+       .flags          = CON_PRINTBUFFER | CON_ANYTIME | CON_CONSDEV,
         .index          = -1,
         .data           = &serial8250_reg,
  };

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The 4.9 has been reverted it, so backport that reverted patch can fix 
this bug, but I don't know why this related to qemumips64?

Thanks

Dengke