Fix shutdown animation cannot be shown

Don't start shutdown critical service or turn off
backlight, when ro.init.shutdown_animation=true

Bug: 196511757
Test: config ro.init.shutdown_animation=true and build
      shutdownanimation.zip to /system/media/
Signed-off-by: zengshuchuan <zengshuchuan@allwinnertech.com>
Change-Id: I5932b7281af630e80247048a70fe1b24f536d1d9