Add break for default cases

Visual Studio has an option to search all files in a solution, so I
did a search in there for "default:" looking for any missing break
statements.

I've left out default statements that return something, and that throw
something, even if via ThrowInvalidType. UNREACHABLE leads towards throw

R_THROW macro leads towards a return

src/video_core/macro/macro_interpreter.cpp

@@ -201,6 +201,7 @@ bool MacroInterpreterImpl::Step(bool is_delay_slot) {
     }
     default:
         UNIMPLEMENTED_MSG("Unimplemented macro operation {}", opcode.operation.Value());
+        break;
     }
 
     // An instruction with the Exit flag will not actually
@@ -297,6 +298,7 @@ void MacroInterpreterImpl::ProcessResult(Macro::ResultOperation operation, u32 r
         break;
     default:
         UNIMPLEMENTED_MSG("Unimplemented result operation {}", operation);
+        break;
     }
 }
 

src/video_core/macro/macro_jit_x64.cpp

@@ -652,6 +652,7 @@ void MacroJITx64Impl::Compile_ProcessResult(Macro::ResultOperation operation, u3
         break;
     default:
         UNIMPLEMENTED_MSG("Unimplemented macro operation {}", operation);
+        break;
     }
 }