mainboard/amd: Sanitise headers in PlatformGnbPcie.c

It is hard to see where things are coming from without correct headers.

Change-Id: I8e2195b101501ffd25464196283fb2bddb5b8f51
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5980
Reviewed-by: Bruce Griffith <Bruce.Griffith@se-eng.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Kconfig: Allow native vga init to be selectable for SeaBIOS payload

Change-Id: I1508f3d3c56cb9afbf4a23355831549552a62866
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/6891
Tested-by: build bot (Jenkins)
Reviewed-by: Kevin O'Connor <kevin@koconnor.net>
Reviewed-by: Martin Roth <gaumless@gmail.com>