drm/amd/display: Fix for otg synchronization logic

[Why]
During otg sync trigger, plane states are used to decide whether the otg
is already synchronized or not. There are scenarions when otgs are
disabled without plane state getting disabled and in such case the otg is
excluded from synchronization.

[How]
Introduced pipe_idx_syncd in pipe_ctx that tracks each otgs master pipe.
When a otg is disabled/enabled, pipe_idx_syncd is reset to itself.
On sync trigger, pipe_idx_syncd is checked to decide whether a otg is
already synchronized and the otg is further included or excluded from
synchronization.

v2:
  Don't drop is_blanked logic

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Mustapha Ghaddar <mustapha.ghaddar@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: meenakshikumar somasundaram <meenakshikumar.somasundaram@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: torvalds@linux-foundation.org
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>