kern: Replace an explicitly instantiated port proxy with one from the tc.

That avoids having to know what type of proxy to create.

Change-Id: I311e770ab720061b52f29df0dcc2273e028aa34a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18578
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
diff --git a/src/kern/linux/helpers.cc b/src/kern/linux/helpers.cc
index ed58427..e514ef8 100644
--- a/src/kern/linux/helpers.cc
+++ b/src/kern/linux/helpers.cc
@@ -94,7 +94,7 @@
 {
     System *system = tc->getSystemPtr();
     const SymbolTable *symtab = system->kernelSymtab;
-    FSTranslatingPortProxy proxy(tc);
+    PortProxy &proxy = tc->getVirtProxy();
 
     Addr addr_lb = 0, addr_lb_len = 0, addr_first = 0, addr_next = 0;
     const bool found_symbols =