partition_data_manager: Take VirtualFile by const reference in constructor

Given the VirtualFile instance isn't stored into the class as a data
member, or written to, this can just be turned into a const reference,
as the constructor doesn't need to make a copy of it.

src/core/crypto/partition_data_manager.cpp

@@ -301,7 +301,7 @@ FileSys::VirtualFile FindFileInDirWithNames(const FileSys::VirtualDir& dir,
     return nullptr;
 }
 
-PartitionDataManager::PartitionDataManager(FileSys::VirtualDir sysdata_dir)
+PartitionDataManager::PartitionDataManager(const FileSys::VirtualDir& sysdata_dir)
     : boot0(FindFileInDirWithNames(sysdata_dir, "BOOT0")),
       fuses(FindFileInDirWithNames(sysdata_dir, "fuse")),
       kfuses(FindFileInDirWithNames(sysdata_dir, "kfuse")),

src/core/crypto/partition_data_manager.h

@@ -23,7 +23,7 @@ class PartitionDataManager {
 public:
     static const u8 MAX_KEYBLOB_SOURCE_HASH;
 
-    explicit PartitionDataManager(FileSys::VirtualDir sysdata_dir);
+    explicit PartitionDataManager(const FileSys::VirtualDir& sysdata_dir);
     ~PartitionDataManager();
 
     // BOOT0