mmc: sdhci-of-aspeed: test: Use kunit_test_suite() macro

The kunit_test_suite() macro is no-longer incompatible with module_add,
so its use can be reinstated.

Since this fixes parsing with builtins and kunit_tool, also enable the
test by default when KUNIT_ALL_TESTS is enabled.

The test can now be run via kunit_tool with:
./tools/testing/kunit/kunit.py run --arch=x86_64 \
--kconfig_add CONFIG_OF=y --kconfig_add CONFIG_OF_ADDRESS=y \
--kconfig_add CONFIG_MMC=y --kconfig_add CONFIG_MMC_SDHCI=y \
--kconfig_add CONFIG_MMC_SDHCI_PLTFM=y \
--kconfig_add CONFIG_MMC_SDHCI_OF_ASPEED=y \
'sdhci-of-aspeed'

(It may be worth adding a .kunitconfig at some point, as there are
enough dependencies to make that command scarily long.)

Acked-by: Daniel Latypov <dlatypov@google.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

mmc: sdhci-of-aspeed: Remove some unnecessary casts from KUnit tests

With KUnit's EXPECT macros no longer typechecking arguments as strictly,
get rid of a number of now unnecessary casts.

Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

mmc: sdhci-of-aspeed: Fix kunit-related build error

Randy found that with the following Kconfig settings we have duplicate
definitions (e.g. __inittest()) in sdhci-of-aspeed due to competing
module_init()/module_exit() calls from kunit and driver the itself.

```
CONFIG_MMC_SDHCI_OF_ASPEED=m
CONFIG_MMC_SDHCI_OF_ASPEED_TEST=y
```

Conditionally open-code the kunit initialisation to avoid the error.

Fixes: 7efa02a981d6 ("mmc: sdhci-of-aspeed: Add KUnit tests for phase calculations")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Link: https://lore.kernel.org/r/20210122114852.3790565-1-andrew@aj.id.au
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: sdhci-of-aspeed: Add KUnit tests for phase calculations

Converting degrees of phase to logic delays is irritating to test on
hardware, so lets exercise the function using KUnit.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20210114031433.2388532-5-andrew@aj.id.au
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>