[llvm] [Offload][NFC] Factor out and rename the `__tgt_offload_entry` struct (PR #123785)

[Shilei Tian via llvm-commits]

================
@@ -21,6 +21,16 @@
 namespace llvm {
 namespace offloading {
 
+/// This is the record of an object that just be registered with the offloading
+/// runtime.
+struct EntryTy {
+  void *Address;
+  char *Symbol;
----------------
shiltian wrote:

nit: `Symbol` instead of `Name`? Maybe `SymbolName`?

https://github.com/llvm/llvm-project/pull/123785