contrib: dracut: Do not timeout waiting for pw

systemd-ask-password has a default timeout of 90 seconds, which means
that dracut will fall back to the rescue shell 4.5 minutes after boot if
no password is entered.

This is undesirable when combined with, for example, unlocking remotely
using dracut-sshd and systemd-tty-ask-password-agent. See also
https://github.com/gsauthof/dracut-sshd#timeout and
https://bugzilla.redhat.com/show_bug.cgi?id=868421.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Clemens Lang <neverpanic@gmail.com>
Closes #14341