Revert "init: Reboot after timeout passes during reboot"

This reverts commit c9fec9d2.

Looks like ext4 can't handle a system reboot happening in the middle
of an unmount.  We'll have to find another way to handle this.

Bug: 74817735
Bug: 75310371
Test: reboot device
Change-Id: Ib4f7f7fd29988a31a99f146c40f6d987c1fef15e