A device's fb_info is shared between clients. fb_release() is called
when each client is released, not just the last one. Since the fbdev
helper needs to release its dma-buf when the last client goes away, it
must keep its own reference count.
fbmem and fbcon hold different locks while calling fb_release(), so
explicit locking is needed.
Change-Id: I42cd659f7633adba7c11f407d4b594bd43305d6a
Signed-off-by: Greg Hackmann <ghackmann@google.com>
