drm/amd: Fix initialization for nbio 4.3.0

drm/amd: Fix initialization for nbio 4.3.0

A mistake has been made on some boards with NBIO 4.3.0 where some
NBIO registers aren't properly set by the hardware.

Ensure that they're set during initialization.

Cc: Natikar Basavaraj <Basavaraj.Natikar@amd.com>
Tested-by: Satyanarayana ReddyTVN <Satyanarayana.ReddyTVN@amd.com>
Tested-by: Rutvij Gajjar <Rutvij.Gajjar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>