Acquire the page lock around vm_page_unwire(). For consistency, extend the

Acquire the page lock around vm_page_unwire().  For consistency, extend the
scope of the object lock in agp_i810.c.  (In this specific case, the scope
of the object lock shouldn't matter, but I don't want to create a bad
example that might be copied to a case where it did matter.)

Reviewed by:	kib