add support for serial console

Change-Id: Ic5054206d77f5e3903a6a917a5046374cc93a0aa

etc/init.rc

@@ -103,11 +103,20 @@ service adbd /system/bin/adbd --root_seclabel=u:r:su:s0 --device_banner=recovery
     socket adbd stream 660 system system
     seclabel u:r:adbd:s0
 
+service console /sbin/sh
+    class core
+    console
+    disabled
+    user root
+    seclabel u:r:shell:s0
+    setenv HOSTNAME console
+
 # Always start adbd on userdebug and eng builds
 on property:ro.debuggable=1
     #write /sys/class/android_usb/android0/enable 1
     #start adbd
     setprop service.adb.root 1
+    start console
 
 # Always start adbd on userdebug and eng builds
 on fs && property:ro.debuggable=1