Revert "posix: procN: add missing alias for getpid()"

This reverts commit be086f174c9bd8c0b62d48e5ff08b2a483b2985d.

PR #73978 introduced a regression.
Unfortunately this PR cannot be reverted without reverting also
Let's revert both PRs to stabilize main again towards the 3.7 release.

For more details on the issue see
https://github.com/zephyrproject-rtos/zephyr/issues/75205

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
1 file changed