universal7904: Switch to default skiaglthreaded renderengine backend

 * Everything seems to be working fine with it
 * also remove renderthread.skia.reduceopstasksplitting prop since it is true by default

Change-Id: I28c3612efc4beb366135e9cd0a6732b0185e8fc2
diff --git a/vendor.prop b/vendor.prop
index bada50d..b9c9499 100644
--- a/vendor.prop
+++ b/vendor.prop
@@ -41,8 +41,6 @@
 
 ## OpenGLES
 ro.opengles.version=196610
-debug.renderengine.backend=threaded
-renderthread.skia.reduceopstasksplitting=true
 
 ## RIL
 vendor.sec.rild.libpath=/vendor/lib64/libsec-ril.so