drm/amd/display: Disable boot optimization for DCN401

[Why]
DCN401 currently has an issue re-enabling when pipe splitting is enabled,
while the root cause is being investigated we can make sure everything is
being reset as a workaround, by disabling boot optimization.

[How]
 - use enable_accelerated_mode instead of init_pipes to fully reset asic

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: Joshua Aberback <joshua.aberback@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>