drm/amd/display: Fix OTG disable workaround logic

[Why]
DENTIST was hanging when performing DISPCLK update with OTG enabled, as
OTG disable workaround was not executing.

[How]
Workaround was checking against current_state before running, but when
called from optimize_bandwidth (safe_to_lower), we should be checking
against context instead.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Hersen Wu <hersenxs.wu@amd.com>
Signed-off-by: Taimur Hassan <syed.hassan@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>