nb/intel/i945: Define and use a default MMCONF_BASE_ADDRESS

Change-Id: I15550b1cc1a7ccfecba68a46ab2acaee820575b9
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/19648
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/northbridge/intel/i945/Kconfig b/src/northbridge/intel/i945/Kconfig
index 98ed630..3bb042e 100644
--- a/src/northbridge/intel/i945/Kconfig
+++ b/src/northbridge/intel/i945/Kconfig
@@ -46,6 +46,10 @@
 	bool
 	default n
 
+config MMCONF_BASE_ADDRESS
+	hex
+	default 0xf0000000
+
 config OVERRIDE_CLOCK_DISABLE
 	bool
 	default n