ANDROID: Allow DRM_IOCTL_MODE_*_DUMB for render clients.

Minigbm uses dumb ioctls when the virtio gpu is in 2D mode. This
changes allows those calls to pass the permission checks in
drm_ioctl_permit().

Bug: b/123764798
Test: booted cuttlefish on drm stack w/o 3d
Change-Id: I872ba8f6d0a284127178dd60f8a2048e5e7397fb
Signed-off-by: Jason Macnak <natsu@google.com>
Signed-off-by: Alistair Delva <adelva@google.com>