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/engines/maxwell_dma.cpp

@@ -311,6 +311,7 @@ void MaxwellDMA::ReleaseSemaphore() {
     }
     default:
         ASSERT_MSG(false, "Unknown semaphore type: {}", static_cast<u32>(type.Value()));
+        break;
     }
 }
 

src/video_core/engines/puller.cpp

@@ -50,6 +50,7 @@ void Puller::ProcessBindMethod(const MethodCall& method_call) {
         break;
     default:
         UNIMPLEMENTED_MSG("Unimplemented engine {:04X}", engine_id);
+        break;
     }
 }
 
@@ -65,6 +66,7 @@ void Puller::ProcessFenceActionMethod() {
         break;
     default:
         UNIMPLEMENTED_MSG("Unimplemented operation {}", regs.fence_action.op.Value());
+        break;
     }
 }
 
@@ -228,6 +230,7 @@ void Puller::CallEngineMethod(const MethodCall& method_call) {
         break;
     default:
         UNIMPLEMENTED_MSG("Unimplemented engine");
+        break;
     }
 }
 
@@ -254,6 +257,7 @@ void Puller::CallEngineMultiMethod(u32 method, u32 subchannel, const u32* base_s
         break;
     default:
         UNIMPLEMENTED_MSG("Unimplemented engine");
+        break;
     }
 }