selftests/damon/access_memory_even: remove unused variables

By reading the code, I found these variables are never referenced in the
code.  Just remove them.

Link: https://lkml.kernel.org/r/20240924021426.1980-1-bajing@cmss.chinamobile.com


Signed-off-by: Ba Jing <bajing@cmss.chinamobile.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>