gpu: host1x: Deduplicate hardware headers

Host1x class information and opcodes are unchanged or backwards
compatible across SoCs so let's not duplicate them for each one
but have them in a shared header file.

At the same time, add opcode functions for acquire/release_mlock.

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