drm/amd/display: Fix pipe addition logic in calc_blocks_to_ungate DCN35

drm/amd/display: Fix pipe addition logic in calc_blocks_to_ungate DCN35

[Why]

Missing check for when there is new pipe configuration but both cur_pipe
and new_pipe are both populated causing update_state of DSC for that
instance not being updated correctly.

This causes some display mode changes to cause underflow since DSCCLK
is still gated when the display requires DSC.

[How]

Added another condition in the new pipe addition branch that checks if
there is a new pipe configuration and if it is not the same as cur_pipe.
cur_pipe does not necessarily have to be NULL to go in this branch.

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