[llvm] [RISCV] Add TuneNoDefaultUnroll to generic CPUs (PR #135318)

[Luke Lau via llvm-commits]

lukel97 wrote:

Looks like this causes quite a few regressions on the BPI-F3, rva22u64_v -O3 -flto: https://lnt.lukelau.me/db_default/v4/nts/419

The code size increases are pretty big. Maybe the unrolling is too aggressive?

https://github.com/llvm/llvm-project/pull/135318