freedreno: add handle and name tracking

Due to the evil userspace buffer tracking we have to do, and hacks for
creating GEM buffer from fbdev/scanout, "evil-twin" fd_bo objects are
problematic.  So introduce hashtable tracking of bo's and dev's, to
avoid getting duplicate fd_bo ptrs for the same underlying gem object,
in particular when importing via flink name.

Signed-off-by: Rob Clark <robclark@freedesktop.org>