ID:176056 Failed to pack DDIO input registers into differential I/Os <name> and <name>

CAUSE: DDIO input registers driven by differential I/Os should be packed into the I/O cells for timing and signal integrity issues. However, at least one of the two registers could not be packed.

ACTION: If the specified differential I/Os have a FAST_INPUT_REGISTER assignment to OFF (thus preventing the packing), remove the assignment.