cluster_placement.h is missing #include vpr_types.h

cluster_placement.h needs vpr_types.h for definitions of t_pack_molecule and t_cluster_placement_stats.

added #include "vpr_types.h" to cluster_placement.h

VPR fails to compile when cluster_placement.h is included in a .cpp file that does not include vpr_types.h earlier in the file.

VPR still compiles and there is no change in QoR (based on quick neuron test referenced in another PR).

[ ] Bug fix (change which fixes an issue)
[ ] New feature (change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to change)

verilog-to-routing / vtr-verilog-to-routing