drm/amd/pm: downgrade log level upon SMU IF version mismatch

SMU IF version mismatch as a warning message exists widely
after asic production, however, due to this log level setting,
such mismatch warning will be caught by automation test like
IGT and reported as a fake error after checking. As such mismatch
does not break anything, to reduce confusion, downgrade it from
dev_warn to dev_info.

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>