linux-phytec-ti

mm/page_ref: introduce page_ref_inc_return

Let's introduce that helper.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>