Grant GPU access to mediaserver

... which will be needed for Cuttlefish with Minigbm
Gralloc 4.

Bug: b/146515640
Test: cts -m CtsGraphicsTestCases -t AImageDecoderTest
Change-Id: I27ae1b2413d45a3d1d88d55ed20452a7b9f1ab7c
diff --git a/shared/sepolicy/vendor/mediaserver.te b/shared/sepolicy/vendor/mediaserver.te
new file mode 100644
index 0000000..922af2c
--- /dev/null
+++ b/shared/sepolicy/vendor/mediaserver.te
@@ -0,0 +1 @@
+gpu_access(mediaserver)