linker: make it less unclear that all the workarounds are ILP32-only.

I'll come back to improve the name of has_min_version(), but i'll need a good suggestion first!

Change-Id: I76ed620768b57b6eb23261627f2cb2ff539c184a
diff --git a/linker/linker_soinfo.cpp b/linker/linker_soinfo.cpp
index b626313..27a5237 100644
--- a/linker/linker_soinfo.cpp
+++ b/linker/linker_soinfo.cpp
@@ -629,47 +629,47 @@
 }
 
 void soinfo::set_realpath(const char* path) {
-#if defined(__work_around_b_24465209__)
+#if defined(__LP64__)
+  realpath_ = path;
+#else
   if (has_min_version(2)) {
     realpath_ = path;
   }
-#else
-  realpath_ = path;
 #endif
 }
 
 const char* soinfo::get_realpath() const {
-#if defined(__work_around_b_24465209__)
+#if defined(__LP64__)
+  return realpath_.c_str();
+#else
   if (has_min_version(2)) {
     return realpath_.c_str();
   } else {
     return old_name_;
   }
-#else
-  return realpath_.c_str();
 #endif
 }
 
 void soinfo::set_soname(const char* soname) {
-#if defined(__work_around_b_24465209__)
+#if defined(__LP64__)
+  soname_ = soname;
+#else
   if (has_min_version(2)) {
     soname_ = soname;
   }
   strlcpy(old_name_, soname_.c_str(), sizeof(old_name_));
-#else
-  soname_ = soname;
 #endif
 }
 
 const char* soinfo::get_soname() const {
-#if defined(__work_around_b_24465209__)
+#if defined(__LP64__)
+  return soname_.c_str();
+#else
   if (has_min_version(2)) {
     return soname_.c_str();
   } else {
     return old_name_;
   }
-#else
-  return soname_.c_str();
 #endif
 }