Add a new dino_pcihost_unrealize() function to remove the address space when the
device is unrealized.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20220504092600.10048-8-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>