[llvm] [AMDGPU] Support block load/store for CSR (PR #130013)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-expensive-checks-debian` running on `gribozavr4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/16/builds/17800

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/AMDGPU/spill-vgpr-block.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/llc -global-isel=1 -mtriple=amdgcn--amdpal -mcpu=gfx1200 -mattr=+block-vgpr-csr < /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/AMDGPU/spill-vgpr-block.ll | /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck -check-prefixes=CHECK,GISEL /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/AMDGPU/spill-vgpr-block.ll # RUN: at line 2
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/llc -global-isel=1 -mtriple=amdgcn--amdpal -mcpu=gfx1200 -mattr=+block-vgpr-csr
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck -check-prefixes=CHECK,GISEL /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/AMDGPU/spill-vgpr-block.ll

# After SI lower SGPR spill instructions
********** INTERVALS **********


```

</details>

https://github.com/llvm/llvm-project/pull/130013