kunit: Use KUNIT_EXPECT_MEMEQ macro

Use KUNIT_EXPECT_MEMEQ to compare memory blocks in replacement of the
KUNIT_EXPECT_EQ macro. Therefor, the statement

    KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

is replaced by:

    KUNIT_EXPECT_MEMEQ(test, foo, bar, size);

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Acked-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>