nb/intel/*/gma.c: Use macros for GMBUS numbers

Change-Id: I885b6bd9f5be6b4e3696a530016123a3e81c4b10
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/20889
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/northbridge/intel/gm45/gma.c b/src/northbridge/intel/gm45/gma.c
index 2404671..00b3fa0 100644
--- a/src/northbridge/intel/gm45/gma.c
+++ b/src/northbridge/intel/gm45/gma.c
@@ -588,8 +588,8 @@
 
 	mmio = res2mmio(gtt_res, 0, 0);
 	printk(BIOS_DEBUG, "VGA EDID\n");
-	intel_gmbus_read_edid(mmio + GMBUS0, 2, 0x50, edid_data_vga,
-			sizeof(edid_data_vga));
+	intel_gmbus_read_edid(mmio + GMBUS0, GMBUS_PORT_VGADDC, 0x50,
+			edid_data_vga, sizeof(edid_data_vga));
 	intel_gmbus_stop(mmio + GMBUS0);
 	vga_edid_status = decode_edid(edid_data_vga,
 				sizeof(edid_data_vga), &edid_vga);
@@ -748,8 +748,8 @@
 	}
 
 	printk(BIOS_DEBUG, "LVDS EDID\n");
-	intel_gmbus_read_edid(mmio + GMBUS0, 3, 0x50, edid_data_lvds,
-			sizeof(edid_data_lvds));
+	intel_gmbus_read_edid(mmio + GMBUS0, GMBUS_PORT_PANEL, 0x50,
+			edid_data_lvds, sizeof(edid_data_lvds));
 	intel_gmbus_stop(mmio + GMBUS0);
 	decode_edid(edid_data_lvds, sizeof(edid_data_lvds), &edid_lvds);