nvptx64: update default alignment to match LLVM 21

This changed in llvm/llvm-project@91cb8f5d32.
The commit itself is mostly about some intrinsic instructions, but as an
aside it also mentions something about addrspace for tensor memory,
which I believe is what this string is telling us.

@rustbot label: +llvm-main

compiler/rustc_codegen_llvm/src/context.rs

@@ -194,6 +194,12 @@ pub(crate) unsafe fn create_module<'ll>(
             target_data_layout = target_data_layout.replace("-i128:128", "");
         }
     }
+    if llvm_version < (21, 0, 0) {
+        if sess.target.arch == "nvptx64" {
+            // LLVM 21 updated the default layout on nvptx: https://github.com/llvm/llvm-project/pull/124961
+            target_data_layout = target_data_layout.replace("e-p6:32:32-i64", "e-i64");
+        }
+    }
 
     // Ensure the data-layout values hardcoded remain the defaults.
     {