wusbcore: Fix one more crypto-on-the-stack bug

The driver put a constant buffer of all zeros on the stack and
pointed a scatterlist entry at it.  This doesn't work with virtual
stacks.  Use ZERO_PAGE instead.

Cc: stable@vger.kernel.org # 4.9 only
Reported-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>