Revert "Revert "[MIPS] Use hard float calling convention for managed code""

This reverts commit 7fee84c087e0f903e7d43bef180df047db1c8051.

Fixed issue with temporary registers on Mips32r6.

Change-Id: I93018927e6a6036cff2d55e6cda66d3212a4316b
diff --git a/runtime/arch/mips/context_mips.cc b/runtime/arch/mips/context_mips.cc
index 53f2b65..bc2bf68 100644
--- a/runtime/arch/mips/context_mips.cc
+++ b/runtime/arch/mips/context_mips.cc
@@ -76,6 +76,11 @@
   gprs_[A1] = nullptr;
   gprs_[A2] = nullptr;
   gprs_[A3] = nullptr;
+
+  fprs_[F12] = nullptr;
+  fprs_[F13] = nullptr;
+  fprs_[F14] = nullptr;
+  fprs_[F15] = nullptr;
 }
 
 extern "C" NO_RETURN void art_quick_do_long_jump(uint32_t*, uint32_t*);