drm/amd/display: S3 Resume time increase after decoupling DPMS from fast boot

[Why]
We incorrectly began powering down the display at boot/resume whenever
fast boot was not possible. This should not be done in the case where there
exists a stream for the eDP since this implies that we want to turn it on.

[How]
Add check for eDP stream to decide whether to power off edp.

Signed-off-by: SivapiriyanKumarasamy <sivapiriyan.kumarasamy@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: Reza Amini <Reza.Amini@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>