mem-ruby: Change request to response in MOESI_AMD_Base-dir.sm

mem-ruby: Change request to response in MOESI_AMD_Base-dir.sm

The responseToDMA MessageBuffer in MOESI_AMD_Base-dir.sm
transmits both data and acks, but it's vnet_type is currently
set as request. This should be changed to response.

Signed-off-by: Sampad Mohapatra <sampad.mohapatra@gmail.com>
Change-Id: I0eb9e8fc8e25111849605a710a5150ce5fc3b83b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33755
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Srikant Bharadwaj <srikant.bharadwaj@amd.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>