Relax neverallow for video_device access

On fugu, surfaceflinger is Graphics Allocator HAL. surfaceflinger
needs access to video_device. This commit thus relaxes the neverallow
rule which says that out of all HALs, only Camera HAL can access
video_device. The rule is relaxed to exclude HALs offered by
framework/system image.

Test: fugu boots
Bug: 37575062
Change-Id: I9b9be55fe0bf3928f1a6342113a7d6f9a2eb0260

public/hal_camera.te

@@ -34,4 +34,4 @@ neverallow hal_camera domain:{ tcp_socket udp_socket rawip_socket } *;
 
 # Only camera HAL may directly access the camera and video hardware
 neverallow { halserverdomain -hal_camera_server } camera_device:chr_file *;
-neverallow { halserverdomain -hal_camera_server } video_device:chr_file *;
+neverallow { halserverdomain -coredomain -hal_camera_server } video_device:chr_file *;