staging: lustre: ko2iblnd: fix memory corruption with fragments

In my test of the upstream client this change exposed a long
standing issues where we have a offset that is not page algined
would causes us to access memory beyond the scatter gather list
which was causing memory corruption when all 256 fragments were
in use.

Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>