staging: lustre: remove obsolete comment in libcfs_hash.h

/*  2^63 + 2^61 - 2^57 + 2^54 - 2^51 - 2^18 + 1 */

#define CFS_GOLDEN_RATIO_PRIME_64 0x9e37fffffffc0001ULL

/*

 * Ideally we would use HAVE_HASH_LONG for this, but on linux we configure

 * the linux kernel and user space at the same time, so we need to differentiate

 * between them explicitly. If this is not needed on other architectures, then

 * we'll need to move the functions to architecture specific headers.

 */

#include <linux/hash.h>

/** disable debug */