Remove extra struct page member from the buffer info structure

declaration.

Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>