Merge adf_device into graphics_device

As of sepolicy commit a16a59e2c7f1e2f09bf7b750101973a974c972e8
(https://android-review.googlesource.com/94580), adf_device
and graphics_device have the exact same security properties.

Merge them into one type to avoid a proliferation of SELinux
types.

Change-Id: Ib1a24f5d880798600e103b9e14934e41abb1ef95
diff --git a/file_contexts b/file_contexts
index fe493d3..8ea7f6d 100644
--- a/file_contexts
+++ b/file_contexts
@@ -31,9 +31,9 @@
 /dev(/.*)?		u:object_r:device:s0
 /dev/akm8973.*		u:object_r:sensors_device:s0
 /dev/accelerometer	u:object_r:sensors_device:s0
-/dev/adf[0-9]*		u:object_r:adf_device:s0
-/dev/adf-interface[0-9]*\.[0-9]*	u:object_r:adf_device:s0
-/dev/adf-overlay-engine[0-9]*\.[0-9]*	u:object_r:adf_device:s0
+/dev/adf[0-9]*		u:object_r:graphics_device:s0
+/dev/adf-interface[0-9]*\.[0-9]*	u:object_r:graphics_device:s0
+/dev/adf-overlay-engine[0-9]*\.[0-9]*	u:object_r:graphics_device:s0
 /dev/alarm		u:object_r:alarm_device:s0
 /dev/android_adb.*	u:object_r:adb_device:s0
 /dev/ashmem		u:object_r:ashmem_device:s0