drm/amdgpu: PWRBRK sequence changes for Aldebaran

Modify power brake enablement sequence on Aldebaran

Signed-off-by: Ashish Pawar <ashish.pawar@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>