remove the unused stdio.hh header

fs/stdio.hh

-#ifndef STDIO_HH_
-#define STDIO_HH_
-
-#include "fs.hh"
-
-class console_file : public file {
-public:
-    virtual uint64_t size();
-    virtual void read(void *buffer, uint64_t offset, uint64_t len);
-    virtual void write(const void* buffer, uint64_t offset, uint64_t len);
-};
-
-extern fileref console_fileref;
-
-#endif /* STDIO_HH_ */