ANDROID: Revert "psi: allow unprivileged users with CAP_SYS_RESOURCE to write psi files"

This reverts commit 6db12ee0.

In Android, system_server registers psi trigger to detect memory
pressure. This commit requires processes registering new triggers to
have CAP_SYS_RESOURCE capability, which system_server does not have.
Reverting this change until a solution can be found to fix the breakage
of functionality in Android T using 5.15 kernels.

Bug: 243781242
Bug: 244148051
Reported-by: liuhailong <liuhailong@oppo.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: If6c8580af8734f3b765d48c782a536aad357e6f0