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/core/hle/kernel/init/init_slab_setup.cpp

@@ -243,6 +243,7 @@ void InitializeSlabHeaps(Core::System& system, KMemoryLayout& memory_layout) {
             // If we somehow get an invalid type, abort.
         default:
             ASSERT_MSG(false, "Unknown slab type: {}", slab_types[i]);
+            break;
         }
 
         // If we've hit the end of a gap, free it.

src/core/hle/kernel/k_page_table.cpp

@@ -2301,6 +2301,7 @@ Result KPageTable::SetProcessMemoryPermission(VAddr addr, size_t size,
             break;
         default:
             ASSERT(false);
+            break;
         }
     }
 
@@ -2803,6 +2804,7 @@ Result KPageTable::Operate(VAddr addr, size_t num_pages, const KPageGroup& page_
             break;
         default:
             ASSERT(false);
+            break;
         }
 
         addr += size;
@@ -2838,6 +2840,7 @@ Result KPageTable::Operate(VAddr addr, size_t num_pages, KMemoryPermission perm,
         break;
     default:
         ASSERT(false);
+        break;
     }
     R_SUCCEED();
 }

src/core/hle/kernel/k_process.cpp

@@ -395,6 +395,7 @@ Result KProcess::LoadFromMetadata(const FileSys::ProgramMetadata& metadata, std:
 
     default:
         ASSERT(false);
+        break;
     }
 
     // Create TLS region