nb/intel/x4x: Fix uninitialized variable issue

A left-over from 5e3cb72a71 (nb/x4x: Do not enable IGD when not
supported). Should fix coverity issue 1375009. Remove a redundant
line that uses the variable `gfxsize` out of its scope and move the
variable declaration. Make sure the variable is always initialized,
drop unneeded error-handling for `get_option()` and sanitize the
read value instead.

Change-Id: Iee2beda30d8c74df0f412622c3ff3357819e386b
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/19680
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
1 file changed