Test ENV: Dragonboard 410c + GG 7.0.1

Test Process:  startup AGL, login a shell via serial or ssh,  execute "reboot" command to reboot system,  but sometimes this reboot action will stop at a point, and the board is in power-off  status.  Please attention this  issue can't be re-produce every time.

[ OK ] Stopped target Network.
Stopping Network Service...
[ OK ] Stopped Load/Save Random Seed.
[ OK ] Stopped Network Service.
[ OK ] Stopped Apply Kernel Variables.
[ OK ] Stopped Load Kernel Modules.
[ OK ] Stopped Update UTMP about System Boot/Shutdown.
[ OK ] Stopped Create Volatile Files and Directories.
[ OK ] Stopped target Local File Systems.
Unmounting Temporary Directory (/tmp)...
Unmounting /var/volatile...
[FAILED] Failed unmounting /run/user/0.
[ OK ] Unmounted Temporary Directory (/tmp).
[ OK ] Unmounted /var/volatile.
[ OK ] Stopped target Swap.
[ OK ] Reached target Unmount All Filesystems.
[ OK ] Stopped target Local File Systems (Pre).
[ OK ] Stopped Create Static Device Nodes in /dev.
[ OK ] Stopped Create System Users.
[ OK ] Stopped Remount Root and Kernel File Systems.
[ OK ] Reached target Shutdown.
telimiting
[ 150.983291] systemd-journald[1679]: Received SIGTERM from PID 1 (systemd-shutdow).
[ 151.021441] systemd-shutdown[1]: Sending SIGKILL to remaining processes...
[ 151.038708] systemd-shutdown[1]: Unmounting file systems.
[ 151.039344] systemd-shutdown[1]: Remounting '/run/user/0' read-only with options 'size=94684k,mode=700'.
[ 151.043238] systemd-shutdown[1]: Unmounting /run/user/0.
[ 151.072207] systemd-shutdown[1]: Remounting '/' read-only with options 'data=ordered'.
[ 151.112018] systemd-shutdown[1]: Remounting '/' read-only with options 'data=ordered'.
[ 151.112113] EXT4-fs (mmcblk0p10): re-mounted. Opts: data=ordered
[ 151.119161] systemd-shutdown[1]: Remounting '/' read-only with options 'data=ordered'.
[ 151.125110] EXT4-fs (mmcblk0p10): re-mounted. Opts: data=ordered
[ 151.132738] systemd-shutdown[1]: All filesystems unmounted.
[ 151.138884] systemd-shutdown[1]: Dea