[Why]
DC configures the GSL group for the pipe when pipe_split is enabled
and we're switching flip types (buffered <-> immediate flip) on DCN2.

In order to record what GSL group the pipe is using DC stores it in
the pipe's stream_res. DM is not aware of this internal grouping, nor
is DC resource.

So when DM creates a dc_state context and passes it to DC the current
GSL group is lost - DM never knew about it in the first place.

After 3 immediate flips we run out of GSL groups and we're no longer
able to correctly perform *any* flip for multi-pipe scenarios.

[How]
The gsl_group needs to be copied to the new context.

DM has no insight into GSL grouping and could even potentially create
a brand new context without referencing current hardware state. So this
makes the most sense to have happen in DC.

There are two places where DC can apply a new context:
- dc_commit_state
- dc_commit_updates_for_stream

But what's shared between both of these is apply_ctx_for_surface.

This logic only matters for DCN2, so it can be placed in
dcn20_apply_ctx_for_surface. Before doing any locking (where the GSL
group is setup) we can copy over the GSL groups before committing the
new context.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Hersen Wu <hersen.wu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>