rosemary: Disable serial console notification

Google added a check for this prop in R, and if it's running
it will show a notification about it that it's impacting performance.
Why it's not disabled by default I don't know, so just force disable
it here.

[bengris32] Convert to standalone init script and install to system_ext

Change-Id: Ia06ef15388e7e701ed526664e7748f133ad01ee2

device.mk

@@ -278,6 +278,7 @@ PRODUCT_PACKAGES += \
     init.mt6785.rc \
     init.mt6785.usb.rc \
     init.sensor_1_0.rc \
+    init.target.rc \
     ueventd.mtk.rc
 
 PRODUCT_PACKAGES += \

rootdir/Android.bp

@@ -51,6 +51,13 @@ prebuilt_etc {
     vendor: true,
 }
 
+prebuilt_etc {
+    name: "init.target.rc",
+    src: "etc/init.target.rc",
+    sub_dir: "init",
+    system_ext_specific: true,
+}
+
 prebuilt_etc {
     name: "ueventd.mtk.rc",
     filename: "ueventd.rc",

rootdir/etc/init.target.rc

@@ -0,0 +1,2 @@
+on boot
+    stop console