commit 71b390e9 upstream.

Now that fetch_pte returns the page-size of the pte, this
function can be optimized a lot.
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>