[llvm] [RISCV][MISched] Set EnableIntervals to true for SiFive7 (PR #75681)

[Francesco Petrogalli via llvm-commits]

fpetrogalli wrote:

> I wonder whether it would be better (in a future patch) to move EnableIntervals out of the scheduler model and add an option like use-intervals-to-schedule so that we can control per-program basis. EnableIntervals isn't really a property of the scheduler model itself, and more a property of how the scheduler behaves.

Please create an [issue](https://github.com/llvm/llvm-project/issues), we will discuss it there.

Thank you!

https://github.com/llvm/llvm-project/pull/75681