[llvm] [RISCV] Adopt SpacemitX60's scheduling model for `-mtune=generic` (PR #167008)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

Alright I just updated all the codegen tests (~700 of them got affected).

I noticed that `test/CodeGen/RISCV/rvv/vfma-vp.ll`...ran out of registers in one of its (LMUL=8) functions:
```
error: <unknown>:0:0: ran out of registers during register allocation in function 'vfma_vv_nxv32bf16'
error: <unknown>:0:0: ran out of registers during register allocation in function 'vfma_vv_nxv32bf16_unmasked'
```
This actually didn't abort the compilation but still raise an error. I marked this test as `XFAIL` at this moment.

https://github.com/llvm/llvm-project/pull/167008