{nb,soc}/intel/{haswell,broadwell}/memmap.c: Use ALIGN_DOWN(x, a)

Change-Id: I049441dd9074659effc1092dce08224974d60a2c
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44924
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/northbridge/intel/haswell/memmap.c

@@ -18,7 +18,7 @@ static uintptr_t smm_region_start(void)
 	 * 1 MiB alignment.
 	 */
 	uintptr_t tom = pci_read_config32(HOST_BRIDGE, TSEG);
-	return tom & ~((1 << 20) - 1);
+	return ALIGN_DOWN(tom, 1 * MiB);
 }
 
 void *cbmem_top_chipset(void)

src/soc/intel/broadwell/memmap.c

@@ -18,7 +18,7 @@ static uintptr_t dpr_region_start(void)
 	 * must be calculated from the size in MiB in bits 11:4.
 	 */
 	uintptr_t dpr = pci_read_config32(SA_DEV_ROOT, DPR);
-	uintptr_t tom = dpr & ~((1 << 20) - 1);
+	uintptr_t tom = ALIGN_DOWN(dpr, 1 * MiB);
 
 	/* Subtract DMA Protected Range size if enabled */
 	if (dpr & DPR_EPM)