[llvm] [X86] Remove unused function createX86PreAMXConfigPass (PR #69547)

[via llvm-commits]

yubingex007-a11y wrote:

i saw https://reviews.llvm.org/D125075 deleted X86PreAMXConfigPass in O0's PM and let O0 use X86FastPreTileConfigPass to insert ldtilecfg. i think we can safely remove X86PreAMXConfigPass 's related code

https://github.com/llvm/llvm-project/pull/69547