tools/testing/nvdimm: add watermarks for dax_pmem* modules

Add nfit_test 'watermarks' for the dax_pmem, dax_pmem_core, and
dax_pmem_compat modules. This causes the nfit_test module to fail
loading in case any of these modules are also not overridden with the
ldconfig wrapped modules. Without this, nfit_test would sometimes fail
creation of device-dax namespaces on the nfit_test_bus with an unhelpful
error log such as:

dax_pmem dax5.0: could not reserve metadata
dax_pmem: probe of dax5.0 failed with error -16

Which was caused due to the unwrapped version of
devm_request_mem_region() being called.

Cc: Dan Williams <[e-mail]>
Signed-off-by: Vishal Verma <[e-mail]>
Signed-off-by: Dan Williams <[e-mail]>

tools/testing/nvdimm/Kbuild

···
 device_dax-y += config_check.o
 
 dax_pmem-y := $(DAX_SRC)/pmem/pmem.o
+dax_pmem-y += dax_pmem_test.o
 dax_pmem_core-y := $(DAX_SRC)/pmem/core.o
+dax_pmem_core-y += dax_pmem_core_test.o
 dax_pmem_compat-y := $(DAX_SRC)/pmem/compat.o
+dax_pmem_compat-y += dax_pmem_compat_test.o
 dax_pmem-y += config_check.o
 
 libnvdimm-y := $(NVDIMM_SRC)/core.o

tools/testing/nvdimm/dax_pmem_compat_test.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2019 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(dax_pmem_compat);

tools/testing/nvdimm/dax_pmem_core_test.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2019 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(dax_pmem_core);

tools/testing/nvdimm/dax_pmem_test.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2019 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(dax_pmem);

tools/testing/nvdimm/test/nfit.c

···
 	acpi_nfit_test();
 	device_dax_test();
 	mcsafe_test();
+	dax_pmem_test();
+	dax_pmem_core_test();
+	dax_pmem_compat_test();
 
 	nfit_test_setup(nfit_test_lookup, nfit_test_evaluate_dsm);
 

tools/testing/nvdimm/watermark.h

···
 int libnvdimm_test(void);
 int acpi_nfit_test(void);
 int device_dax_test(void);
+int dax_pmem_test(void);
+int dax_pmem_core_test(void);
+int dax_pmem_compat_test(void);
 
 /*
  * dummy routine for nfit_test to validate it is linking to the properly