[PATCH] USB UHCI: Fix up loose ends

This patch tidies up a few loose ends left by the preceding patches.
It indicates the controller supports remote wakeup whenever the PM
capability is present -- which shouldn't cause any harm if the
assumption turns out to be wrong.  It refuses to suspend the
controller if the root hub is still active, and it refuses to resume
the root hub if the controller is suspended.  It adds checks for a
dead controller in several spots, and it adds memory barriers as
needed to insure that I/O operations are completed before moving on.

Actually I'm not certain the last part is being done correctly.  With
code like this:

	outw(..., ...);
	mb();
	udelay(5);

do we know for certain that the outw() will complete _before_ the
delay begins?  If not, how should this be written?

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>