drm/amd: Fix initialization for nbio 7.5.1

A mistake has been made in the BIOS for some ASICs with NBIO 7.5.1
where some NBIO registers aren't properly setup.

Ensure that they're set during initialization.

Tested-by: Richard Gong <richard.gong@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.1.x