drm/amdgpu: Use function pointer for some mmhub functions

Add more function pointers to amdgpu_mmhub_funcs. ASIC specific
implementation of most mmhub functions are called from a general
function pointer, instead of calling different function for
different ASIC. Simplify the code by deleting duplicate functions

Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: Export setup_vm_pt_regs() logic for mmhub 2.0

The KFD code will call this function later.

Signed-off-by: Yong Zhao <Yong.Zhao@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: add mmhub v2 block for navi10 (v4)

mmhub is the memory controller hub for multi-media (VCN).

v1: add place holder and initial functions (Ray)
v2: replace legacy amdgpu_mc structure with amdgpu_gmc (Hawking)
v3: switch to use amdgpu_gmc_pd_addr (Hawking)
v4: squash in updates (Alex)

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>