Remove libskia.so from the greylist

The library is no longer available on the devices.

Bug: http://b/31971097
Test: make
Change-Id: Ie87bb8a8c200d086d272ca923242bfbab6397126
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 0a931c6..7e72b27 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -189,7 +189,6 @@
     "libgui.so",
     "libmedia.so",
     "libnativehelper.so",
-    "libskia.so",
     "libssl.so",
     "libstagefright.so",
     "libsqlite.so",