drivers/intel/gma/acpi: Provide default definition for displays

Use it wherever the standard numbers were copied to. Bit 31 is set
at runtime unconditionally, so we don't need it here.

Change-Id: I0d853c3b8250a2c7b2d1a91985a555e4b17ad76c
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39731
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/lenovo/x60/devicetree.cb b/src/mainboard/lenovo/x60/devicetree.cb
index 2ebd981..fbe13d8 100644
--- a/src/mainboard/lenovo/x60/devicetree.cb
+++ b/src/mainboard/lenovo/x60/devicetree.cb
@@ -15,8 +15,7 @@
 
 chip northbridge/intel/i945
 	# IGD Displays
-	register "gfx.ndid" = "3"
-	register "gfx.did" = "{ 0x80000100, 0x80000240, 0x80000410, 0x80000410, 0x00000005 }"
+	register "gfx" = "GMA_STATIC_DISPLAYS(0)"
 
 	register "gpu_hotplug" = "0x00000220"
 	register "gpu_lvds_use_spread_spectrum_clock" = "1"