drm/amd: Revert "drm/amd/display: keep eDP Vdd on when eDP stream is already enabled"

A variety of Lenovo machines with Rembrandt APUs and OLED panels have
stopped showing the display at login.  This behavior clears up after
leaving it idle and moving the mouse or touching keyboard.

It was bisected to be caused by commit 559e2655 ("drm/amd/display:
keep eDP Vdd on when eDP stream is already enabled").  Revert this commit
to fix the issue.

Link: amd#2047


Reported-by: Aaron Ma <aaron.ma@canonical.com>
Fixes: 559e2655 ("drm/amd/display: keep eDP Vdd on when eDP stream is already enabled")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Mark Pearson <markpearson@lenovo.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>