kernel: Properly expose block device sizes with the new metadata API

kernel/src/fs/tmpfs/FileSystem.cpp

@@ -70,6 +70,7 @@ namespace TmpFS
         inode->set_device_id(luna_dev_makedev(major, minor), {});
         inode->m_metadata.mode = mode;
         inode->m_metadata.atime = inode->m_metadata.ctime = inode->m_metadata.mtime = *Timer::realtime_clock();
+        inode->m_metadata.size = device->size();
 
         return (SharedPtr<VFS::Inode>)inode;
     }