sim-se: const for loader's loadSection param

The port proxy can be declared as a reference to a const proxy
rather than just a reference to a proxy.

Change-Id: I4640b0c5f33e2334c1e7630131f78607ced40a34
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/12301
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

src/base/loader/object_file.hh

@@ -88,7 +88,7 @@ class ObjectFile
 
     static const Addr maxAddr = std::numeric_limits<Addr>::max();
 
-    virtual bool loadSections(PortProxy& mem_proxy,
+    virtual bool loadSections(const PortProxy& mem_proxy,
                               Addr mask = maxAddr, Addr offset = 0);
 
     virtual bool loadAllSymbols(SymbolTable *symtab, Addr base = 0,
@@ -129,7 +129,7 @@ class ObjectFile
     Section data;
     Section bss;
 
-    bool loadSection(Section *sec, PortProxy& mem_proxy, Addr mask,
+    bool loadSection(Section *sec, const PortProxy& mem_proxy, Addr mask,
                      Addr offset = 0);
     void setGlobalPointer(Addr global_ptr) { globalPtr = global_ptr; }