drm/amd/display: Restore 5s vbl offdelay for NV3x+ DGPUs

drm/amd/display: Restore 5s vbl offdelay for NV3x+ DGPUs

[Why]

Rapid vblank off is causing flip-done timeouts for NV3x and newer
family of GPUs that support more idle optimization features.

A proper fix requires further investigation. In lieu of it, let's
workaround it for now.

[How]

For NV3x and newer family of DGPUs, restore the old 5s vblank off timer.

Fixes: 9b47278cec98 ("drm/amd/display: temp w/a for dGPU to enter idle optimizations")
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3787
Link: https://lore.kernel.org/amd-gfx/20260217191632.1243826-1-sysdadmin@m1k.cloud/
Tested-by: Michele Palazzi <sysdadmin@m1k.cloud>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>