Floating Point Unit is instantiated in CORE-V-MCU

The CORE-V-MCU instantiates the "fpnew" floating point IP from the pulp-platform team. As discussed in #189 (closed), the CV32E40P does not make use of this floating point unit, so it really should not be there.

Note: I have labelled this as a bug for two reasons:

1. Instantiating fpnew and connecting it to the core via the APU bus may cause unintended behaviour. This has not been tested for.
2. Physical Implementation: even if the instantiating and connecting fpnew does not cause a functional bug, it is not good practise to include a lot of unused logic.