nitro_enclaves: test: Use kunit_test_suite() macro

The kunit_test_suite() macro previously conflicted with module_init,
making it unsuitable for use in the nitro_enclaves test. Now that it's
fixed, we can use it instead of a custom call into internal KUnit
functions to run the test.

As a side-effect, this means that the test results are properly included
with other suites when built-in. To celebrate, enable the test by
default when KUNIT_ALL_TESTS is set (and NITRO_ENCLAVES enabled).

The nitro_enclave tests can now be run via kunit_tool with:
./tools/testing/kunit/kunit.py run --arch=x86_64 \
--kconfig_add CONFIG_PCI=y --kconfig_add CONFIG_SMP=y \
--kconfig_add CONFIG_HOTPLUG_CPU=y \
--kconfig_add CONFIG_VIRT_DRIVERS=y \
--kconfig_add CONFIG_NITRO_ENCLAVES=y \
'ne_misc_dev_test'

(This is a pretty long command, so it may be worth adding a .kunitconfig
file at some point, instead.)

Reviewed-by: Andra Paraschiv <andraprs@amazon.com>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

nitro_enclaves: Add KUnit tests for contiguous physical memory regions merging

Add KUnit tests for the contiguous physical memory regions merging
functionality from the Nitro Enclaves misc device logic.

We can build the test binary with the following configuration:
CONFIG_KUNIT=y
CONFIG_NITRO_ENCLAVES=m
CONFIG_NITRO_ENCLAVES_MISC_DEV_TEST=y
and install the nitro_enclaves module to run the testcases.

We'll see the following message using dmesg if everything goes well:

[...] # Subtest: ne_misc_dev_test
[...] 1..1
[...] (NULL device *): Physical mem region address is not 2 MiB aligned
[...] (NULL device *): Physical mem region size is not multiple of 2 MiB
[...] (NULL device *): Physical mem region address is not 2 MiB aligned
[...] ok 1 - ne_misc_dev_test_merge_phys_contig_memory_regions
[...] ok 1 - ne_misc_dev_test

Reviewed-by: Andra Paraschiv <andraprs@amazon.com>
Signed-off-by: Longpeng <longpeng2@huawei.com>
Link: https://lore.kernel.org/r/20211107140918.2106-5-longpeng2@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nitro_enclaves: Add KUnit tests setup for the misc device functionality

Add the initial setup for the KUnit tests that will target the Nitro
Enclaves misc device functionality.

Reviewed-by: Andra Paraschiv <andraprs@amazon.com>
Signed-off-by: Longpeng <longpeng2@huawei.com>
Link: https://lore.kernel.org/r/20211107140918.2106-4-longpeng2@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>