romfs_factory: Remove unnecessary includes and use forward declarations where applicable

Avoids the need to rebuild whatever includes the romfs factory header if
the loader header ever changes. We also don't need to include the main
core header. We can instead include the headers we specifically need.

src/core/file_sys/nca_metadata.h

@@ -7,6 +7,7 @@
 #include <cstring>
 #include <memory>
 #include <vector>
+#include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
 #include "core/file_sys/vfs.h"

src/core/file_sys/romfs_factory.cpp

@@ -6,15 +6,17 @@
 #include <memory>
 #include "common/common_types.h"
 #include "common/logging/log.h"
-#include "core/core.h"
+#include "core/file_sys/nca_metadata.h"
 #include "core/file_sys/romfs_factory.h"
 #include "core/hle/kernel/process.h"
+#include "core/hle/service/filesystem/filesystem.h"
+#include "core/loader/loader.h"
 
 namespace FileSys {
 
 RomFSFactory::RomFSFactory(Loader::AppLoader& app_loader) {
     // Load the RomFS from the app
-    if (Loader::ResultStatus::Success != app_loader.ReadRomFS(file)) {
+    if (app_loader.ReadRomFS(file) != Loader::ResultStatus::Success) {
         LOG_ERROR(Service_FS, "Unable to read RomFS!");
     }
 }

src/core/file_sys/romfs_factory.h

@@ -6,11 +6,17 @@
 
 #include <memory>
 #include "common/common_types.h"
+#include "core/file_sys/vfs.h"
 #include "core/hle/result.h"
-#include "core/loader/loader.h"
+
+namespace Loader {
+class AppLoader;
+} // namespace Loader
 
 namespace FileSys {
 
+enum class ContentRecordType : u8;
+
 enum class StorageId : u8 {
     None = 0,
     Host = 1,