allow respond to read transactions between address write and data write to speed up response

[AngelaGonzalezMarino]

Current implementation goes to wait valid state after receiving an address write, until the data write comes
The proposal is to permit to respond to read requests that may come in between to speed up the response time

This is useful for example when integrating a DMA

We have tested this change with the CVA6 smoke tests and benchmarks, apart from our own integration tests with other peripherals such as DMA.

[AngelaGonzalezMarino]

Hi @andreaskurth,
I've seen you approved the latest PR here (although 2 years ago).
Do you know who could have a look at this?
Thanks!