Randy has moved

Update email address and CREDITS info.  xenotime.net is defunct.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Harry Wei <harryxiyou@gmail.com>
Cc: Keiichi KII <k-keiichi@bx.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>