Add Quiescent Reboot Target

[Description]
In the Quiescent Reboot process,
the android init process will pass the reboot target name "quiescent"
to the kernel through reboot syscall.

Kernel will write the boot-quiescent flag
to the misc partition to notify the bootloader.

When rebooting, bootloader will be added to
bootargs androidboot.quiescent=1 to notify android .

In the new version of GKI,
the filp_open function is not allowed
so that it is impossible to write the quiescent flag
in the Kernel to the misc partition.

https://android-review.googlesource.com/c/kernel/common/+/1705108
/1..29/android/abi_gki_aarch64_mtk#b641

Bug: 192634025

Test:
adb reboot quiescent
adb shell setprop sys.powerctl reboot,quiescent

Change-Id: I5ac982a1f16df39fa6bf567729a18ca8225f21f2