drm/amd/display: Increase number of hpo dp link encoders

[Why]
Number of hpo dp2 link encoders is increased.
Instances are changed.

[How]
Increased size in resource pool, init for each instance

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Sridevi Arvindekar <sridevi.arvindekar@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>