[TableGen] Add support for per-write cycle tunables (#125870)

This patch adds support for describing per-write resource cycle counts
for ReadAdvance records via a new optional field called `tunables`.
    
This makes it possible to declare ReadAdvance records such as:
    
      def : ReadAdvance<Read_C, 1, [Write_A, Write_B], [2]>;
    
The above will effectively declare two entries in the ReadAdvance
table for Read_C, one for Write_A with a cycle count of 1+2, and one for
Write_B with a cycle count of 1+0 (omitted values are assumed 0).
    
The field `tunables` provides a list of deltas relative to the base
`cycle` count of the ReadAdvance. Since the field is optional and
defaults to a list of 0's, this change doesn't affect current targets.

0 files changed, 0 insertions, 0 deletions