tests,configs,mem-ruby: Handle num DMAs in GPU Ruby tester
tests,configs,mem-ruby: Handle num DMAs in GPU Ruby tester

Currently the GPU Ruby tester does not support requests returned
as aliased.  To get around this, the GPU Ruby tester needs
numDMAs to be 0.  To enable this, change the default value to allow
us to identify when a user wants more DMAs.

Change-Id: I0a31f66c831f0379544c15bd7364f185e1edb1b2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57535
Maintainer: Matt Sinclair <d2406197fb1bedd1e23c70c50c510ff0e9ab0f5b@gmail.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Matthew Poremba <f1eb50f3368ce197c52b19f7fdb5aa7a278f15fd@amd.com>

gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5