gpu: nvgpu: NVENC support on TU104

This patch adds nvenc support for TU104
- Fetch engine/dev info for nvenc
- Falcon NS boot (fw loading) support
- Engine context creation for nvenc
- Skip golden image for multimedia engines
- Avoid subctx for nvenc as it is a non-VEID engine
- Job submission/flow changes for nvenc
- Code refactoring to scale up the support for other multimedia
  engines in future.

Bug 3763551

Change-Id: I03d4e731ebcef456bcc5ce157f3aa39883270dc0
Signed-off-by: Santosh BS <santoshb@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2859416
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc-mobile-cert <svc-mobile-cert@nvidia.com>
Reviewed-by: Rajesh Devaraj <rdevaraj@nvidia.com>
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

include/uapi/linux/nvgpu-ctrl.h

@@ -672,6 +672,7 @@ struct nvgpu_gpu_get_engine_info_item {
 #define NVGPU_GPU_ENGINE_ID_GR 0
 #define NVGPU_GPU_ENGINE_ID_GR_COPY 1
 #define NVGPU_GPU_ENGINE_ID_ASYNC_COPY 2
+#define NVGPU_GPU_ENGINE_ID_NVENC 5
 	__u32 engine_id;
 
 	__u32 engine_instance;