intel/gma: Use defines for registers and values in edid.c

This replaces magic values with defines without changing any value.

Change-Id: I332442045aa4a28ffed88fc52a99a4364684f00c
Signed-off-by: Sebastian "Swift Geek" Grzywna <swiftgeek@gmail.com>
Reviewed-on: https://review.coreboot.org/16339
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Nico Huber <nico.h@gmx.de>
1 file changed