xorg: fix VESA int10 error

xorg: fix VESA int10 error

When falling back to the VESA server, X fails to start due to an error
reading the int10 vec.

We cherry-pick the following commit to fix the error:

   commit 0a78b599b34cc8b5fe6fe82f90e90234e8ab7a56
   Author: Jürg Billeter <j@bitron.ch>
   Date:   Sat Feb 7 18:13:21 2015 +0100

       int10: Fix error check for pci_device_map_legacy

       pci_device_map_legacy returns 0 on success.

       Signed-off-by: Jürg Billeter <j@bitron.ch>
       Reviewed-by: Adam Jackson <ajax@redhat.com>
       Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(From OE-Core rev: e1570e12f92bf359ef34d0e2998b09981bcece18)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>