selftests/powerpc: Remove the path after initialization.

If there were no anamolies noted, then we can simply remove the log file
and return, but only after the path variable has been initialized.

Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20240930012757.2395-1-zhangjiao2@cmss.chinamobile.com