change(vfs): make fs_root inline global var

include/kernel/vfs.hpp

@@ -162,7 +162,7 @@ public:
     virtual int inode_stat(dentry* dir, stat* stat);
 };
 
-extern fs::vfs::dentry* fs_root;
+inline fs::vfs::dentry* fs_root;
 
 void register_special_block(uint16_t major,
     uint16_t minor,

src/kernel/vfs.cpp

@@ -439,7 +439,6 @@ int fs::vfs_stat(fs::vfs::dentry* ent, stat* stat)
     return ent->ind->fs->inode_stat(ent, stat);
 }
 
-fs::vfs::dentry* fs::fs_root;
 static types::list<fs::vfs*>* fs_es;
 
 void fs::register_special_block(