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