device: Remove unused <cbmem.h>

Change-Id: I81bf00af1b56a0181c376db92f5f85297b6993ed
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61050
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/device/dram/lpddr4.c

@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <console/console.h>
-#include <cbmem.h>
 #include <device/device.h>
 #include <device/dram/lpddr4.h>
 #include <memory_info.h>