- Update stale url to documentation

From: Kyle McMartin <kyle@parisc-linux.org>

 - Make unwinding from modules work, mostly
 - Fix unwinding from millicode
Signed-off-by: Randolph Chung <tausq@debian.org>
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>