gpu: host1x: Add option to skip firewall for a job

The new UAPI will have its own firewall, and we don't want to run
the firewall in the Host1x driver for those jobs. As such, add a
parameter to host1x_job_alloc to specify if we want to skip the
firewall in the Host1x driver.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>