staging: gasket: page_table: remove unnecessary PTE status set to free

Remove unnecessary ptes[i].status update in gasket_perform_unmapping.
The vaaue will be cleared in the following memset.

Signed-off-by: Nick Ewalt <nicholasewalt@google.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>