Fix copy and paste error in jiffies_to_AHZ conversion which leads to wrong
BSD accounting information on alpha and ia64 when
CONFIG_BSD_PROCESS_ACCT_V3 is turned on.

Also update comment to match reorganised header files.
Signed-off-by: NTim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>