x86, uv: Update UV arch to target Legacy VGA I/O correctly.

Add function to direct Legacy VGA I/O traffic to correct I/O Hub.

Signed-off-by: Mike Travis <travis@sgi.com>
LKML-Reference: <201002022238.o12McEbi018727@imap1.linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>