nb/intel/x4x/iomap.h: Rename to memmap.h

It primarily contains definitions for MMIO windows. Also, remove
includes from files not directly using the definitions it contains.

Tested with BUILD_TIMELESS=1, Asus P5QL PRO remains identical.

Change-Id: Id28080d9b2924463dd3720492d5e717d65fa0071
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45419
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/northbridge/intel/x4x/bootblock.c

@@ -5,7 +5,6 @@
 #include <device/pci_ops.h>
 
 #include "x4x.h"
-#include "iomap.h"
 
 void bootblock_early_northbridge_init(void)
 {