drm/amd/display: Revert "Improve x86 and dmub ips handshake"

This reverts commit 1288d702.

Causes intermittent hangs during reboot stress testing.

Reviewed-by: Duncan Ma <duncan.ma@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>