[MISched] Use SchedRegion in overrideSchedPolicy and overridePostRASchedPolicy (#149297)

This patch updates `overrideSchedPolicy` and `overridePostRASchedPolicy`
to take a
`SchedRegion` parameter instead of just `NumRegionInstrs`. This provides
access to both the
instruction range and the parent `MachineBasicBlock`, which enables
looking up function-level
attributes.

With this change, targets can select post-RA scheduling direction per
function using a function
attribute. For example:

```cpp
void overridePostRASchedPolicy(MachineSchedPolicy &Policy,
                               const SchedRegion &Region) const {
  const Function &F = Region.RegionBegin->getMF()->getFunction();
  Attribute Attr = F.getFnAttribute("amdgpu-post-ra-direction");
  ...
}

0 files changed, 0 insertions, 0 deletions