staging/lustre: Remove unused debugfs/procfs helpers

These particular helpers are unused so let's get rid of them:
ldebugfs_add_symlink, lprocfs_rd_u64, lprocfs_rd_atomic,
lprocfs_wr_atomic, lprocfs_rd_name, lprocfs_seq_read_frac_helper

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>