CBMEM intel: Define get_top_of_ram() once per chipset

Only have one definition of get_top_of_ram() function and compile
it using __SIMPLE_DEVICE__ for both romstage and ramstage.

Implemented like this on intel/northbridge/gm45 already.
This also adds get_top_of_ram() to i945 ramstage.

Change-Id: Ia82cf6e47a4c929223ea3d8f233d606e6f5bf2f1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3993
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/src/northbridge/intel/haswell/Makefile.inc b/src/northbridge/intel/haswell/Makefile.inc
index 04b0d2f..bf7daa7 100644
--- a/src/northbridge/intel/haswell/Makefile.inc
+++ b/src/northbridge/intel/haswell/Makefile.inc
@@ -17,6 +17,7 @@
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 #
 
+ramstage-y += ram_calc.c
 ramstage-y += northbridge.c
 ramstage-y += gma.c
 
@@ -24,6 +25,7 @@
 ramstage-y += mrccache.c
 ramstage-y += minihd.c
 
+romstage-y += ram_calc.c
 romstage-y += raminit.c
 romstage-y += mrccache.c
 romstage-y += early_init.c