minijail: allow readlink syscall for media.codec

Change-Id: I9e1d43fdd0126c338a5c3e70eef441c873e5643c
diff --git a/conf_files/kona/mediacodec-seccomp.policy b/conf_files/kona/mediacodec-seccomp.policy
index 3bf11a3..0b75b84 100644
--- a/conf_files/kona/mediacodec-seccomp.policy
+++ b/conf_files/kona/mediacodec-seccomp.policy
@@ -17,3 +17,5 @@
 timer_create: 1
 timer_settime: 1
 rt_sigtimedwait: 1
+readlink: 1
+open: 1