drm/amdgpu/psp: add psp support for navi14 (v3)

Same as navi10.

v2: squash in logic fix (Colin Ian King)
v3: squash in logic simplification (Alex)

Signed-off-by: Xiaojie Yuan <xiaojie.yuan@amd.com>
Reviewed-by: Snow Zhang <Snow.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>