Avoid the more cpu expensive kzalloc when allocating buffers.
Originally kzalloc was intended for isolating the guest from
the host by not sending random guest data to the host. But device
isolation is not yet in place so kzalloc is not really needed.
Signed-off-by: NSjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>