Revert "posix: device_io: use mode argument correctly in open()"

This reverts commit 499a6339764b51f2ebde2081c33fc1936be9b8dd.

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>
7 files changed