northbridge/intel: Rename ram_calc.c to memmap.c

Use a name consistent with the more recent soc/intel.

Change-Id: Ie69583f28f384eb49517203e1c3867f27e6272de
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34699
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/northbridge/intel/i440bx/Makefile.inc b/src/northbridge/intel/i440bx/Makefile.inc
index d41f65d..2c503c6 100644
--- a/src/northbridge/intel/i440bx/Makefile.inc
+++ b/src/northbridge/intel/i440bx/Makefile.inc
@@ -17,12 +17,12 @@
 ifeq ($(CONFIG_NORTHBRIDGE_INTEL_I440BX),y)
 
 ramstage-y += northbridge.c
-ramstage-y += ram_calc.c
+ramstage-y += memmap.c
 
 romstage-y += raminit.c
 romstage-$(CONFIG_DEBUG_RAM_SETUP) += debug.c
-romstage-y += ram_calc.c
+romstage-y += memmap.c
 
-postcar-y += ram_calc.c
+postcar-y += memmap.c
 
 endif