drm/amdgpu: Move KFD parameters to amdgpu (v3)

After merging KFD into amdgpu, move module parameters defined in KFD to
amdgpu_drv.c, where other module parameters are declared.

v2: add kernel-doc comments
v3: rebase and fix parameter variable name (Alex)

Signed-off-by: Amber Lin <Amber.Lin@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>