[BACKEND] Update LLVM version to llvm/llvm-project@1a9acd7 (triton-lang#4468)

Author: chsigg

cmake/llvm-hash.txt

@@ -1 +1 @@
-99bb9a719cec9513e72ad275c1c0302b76b6c408
+1a9acd786d493b00c08d1611f51420d421b74cf1

third_party/amd/lib/TritonAMDGPUToLLVM/BuiltinFuncToLLVM.cpp

@@ -128,7 +128,7 @@ class CallOpConversion : public mlir::RewritePattern {
     auto operands = callOp.getOperands();
     auto result = callOp.getResult();
 
-    LLVM::LLVMFunctionType calleeType = callOp.getVarCalleeType().value();
+    LLVM::LLVMFunctionType calleeType = callOp.getCalleeFunctionType();
     Type returnType = calleeType.getReturnType();
 
     auto loc = callOp.getLoc();