kunit: move KUNIT_TABLE out of INIT_DATA

Alter the linker section of KUNIT_TABLE to move it out of INIT_DATA and
into DATA_DATA.

Data for KUnit tests does not need to be in the init section.

In order to run tests again after boot the KUnit data cannot be labeled as
init data as the kernel could write over it.

Add a KUNIT_INIT_TABLE in the next patch for KUnit tests that test init
data/functions.

Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Rae Moar <rmoar@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>