drm/amd/powerplay: drop redundant BIF doorbell interrupt operations

This is already done in soc15.c. And this is really ASIC specific
and should not be placed here.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed