vfs: Amend constness on pointers in WriteBytes() and WriteArrays() member functions to be const qualified

These functions don't modify the data being pointed to, so these can be
pointers to const data

src/core/file_sys/vfs.h

@@ -93,7 +93,7 @@ struct VfsFile : NonCopyable {
     // Writes an array of type T, size number_elements to offset in file.
     // Returns the number of bytes (sizeof(T)*number_elements) written successfully.
     template <typename T>
-    size_t WriteArray(T* data, size_t number_elements, size_t offset = 0) {
+    size_t WriteArray(const T* data, size_t number_elements, size_t offset = 0) {
         static_assert(std::is_trivially_copyable<T>::value,
                       "Data type must be trivially copyable.");
 
@@ -103,10 +103,10 @@ struct VfsFile : NonCopyable {
     // Writes size bytes starting at memory location data to offset in file.
     // Returns the number of bytes written successfully.
     template <typename T>
-    size_t WriteBytes(T* data, size_t size, size_t offset = 0) {
+    size_t WriteBytes(const T* data, size_t size, size_t offset = 0) {
         static_assert(std::is_trivially_copyable<T>::value,
                       "Data type must be trivially copyable.");
-        return Write(reinterpret_cast<u8*>(data), size, offset);
+        return Write(reinterpret_cast<const u8*>(data), size, offset);
     }
 
     // Writes one object of type T to offset in file.