Revert of Add unoptimized/optimized variants of MathFloor TF code stub

src/mips64/interface-descriptors-mips64.cc

Index: src/mips64/interface-descriptors-mips64.cc
diff --git a/src/mips64/interface-descriptors-mips64.cc b/src/mips64/interface-descriptors-mips64.cc
index 47cc0923cb8f0b7009fededac3770740c295372a..689bbbb9ee392cf13160ebffb6b1417251cbaacd 100644
--- a/src/mips64/interface-descriptors-mips64.cc
+++ b/src/mips64/interface-descriptors-mips64.cc
@@ -330,25 +330,14 @@
 }
 
 
-void MathRoundVariantCallFromUnoptimizedCodeDescriptor::
-    InitializePlatformSpecific(CallInterfaceDescriptorData* data) {
+void MathRoundVariantDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
   Register registers[] = {
       a1,  // math rounding function
       a3,  // vector slot id
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
-
-
-void MathRoundVariantCallFromOptimizedCodeDescriptor::
-    InitializePlatformSpecific(CallInterfaceDescriptorData* data) {
-  Register registers[] = {
-      a1,  // math rounding function
-      a3,  // vector slot id
-      a2,  // type vector
-  };
-  data->InitializePlatformSpecific(arraysize(registers), registers);
-}
 }  // namespace internal
 }  // namespace v8