drm/amd/display: Pass up errors for reset GPU that fails to init HW

[Why]
If a GPU is in reset and the hardware fails to initialize the rest of the
resume sequence shouldn't be run.

[How]
Pass error code up to caller of dm_resume().

Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org