[MIPS] Support FR=0 emulation on FR=1 64-bit FP registers

Enables running of older MIPS NDK-built apps on mips64r6.

Works with kernel supporting FRE emulation, and old kernels.

Change-Id: I13923fe62cd83ad1d337f13a50f2eda2dfdd906f
diff --git a/linker/linker.h b/linker/linker.h
index b64f42c..43b1e07 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -250,7 +250,9 @@
   bool mips_relocate_got(const VersionTracker& version_tracker,
                          const soinfo_list_t& global_group,
                          const soinfo_list_t& local_group);
-
+#if !defined(__LP64__)
+  bool mips_check_and_adjust_fp_modes();
+#endif
 #endif
   size_t ref_count_;
  public: