sm8450-common: rootdir: Set hardware revision property

The bootloader sets androidboot.hwversion, use this and set the ro.boot.hardware.revision property in order to show it in settings.

Change-Id: I3c6c678bf055091ea9fcb2a1524d321e2c1be043

rootdir/etc/init.xiaomi_sm8450.rc

@@ -129,3 +129,6 @@ service vendor.sensors-hal-2-1-multihal /vendor/bin/hw/android.hardware.sensors@
     capabilities BLOCK_SUSPEND
     rlimit rtprio 10 10
     socket audio_us_socket_1 seqpacket 0666 system system
+
+on property:ro.boot.hwversion=*
+    setprop ro.boot.hardware.revision ${ro.boot.hwversion}