drm/amdgpu: read harvest bit per IP data on legacy GPUs

Based on firmware team's input, harvest table in VBIOS does
not apply well to legacy products like Navi1x, so seperate
harvest mask configuration retrieve from different places.
On legacy GPUs, scan harvest bit per IP data stuctures,
while for newer ones, still read IP harvest info from harvest
table.

v2: squash in fix to limit it to specific skus (Guchun)

Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>