sandbox64: add a test case for UCLASS_NVMXIP

provide a test for NVM XIP devices

The test case allows to make sure of the following:

- The NVM XIP QSPI devices are probed
- The DT entries are read correctly
- the data read from the flash by the NVMXIP block driver is correct

Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index e15bdbf..c8534b5 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0+
 #
 # Copyright (c) 2013 Google, Inc
+# Copyright 2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
 
 obj-$(CONFIG_UT_DM) += test-dm.o
 
@@ -17,6 +18,10 @@
 obj-$(CONFIG_UT_DM) += core.o
 obj-$(CONFIG_UT_DM) += read.o
 obj-$(CONFIG_UT_DM) += phys2bus.o
+ifeq ($(CONFIG_NVMXIP_QSPI)$(CONFIG_SANDBOX64),yy)
+obj-y += nvmxip.o
+endif
+
 ifneq ($(CONFIG_SANDBOX),)
 ifeq ($(CONFIG_ACPIGEN),y)
 obj-y += acpi.o