Allow init to set powerctl property
NIAP certification requires that all cryptographic functions
undergo a self-test during startup to demonstrate correct
operation. init now performs this check during startup.
The self-test is forked from init. For the child process
to be able to request a reboot it needs permissions to
set the sys.powerctl property.
Test: Built for walleye. When the BoringSSL self test was forced
to fail the device rebooted into the bootloader, as
2 files changed