[PATCH] ppc64: Fix typo in time calculations

This fixes a typo in the div128_by_32 function used in the timekeeping
calculations on ppc64.  If you look at the code it's quite obvious
that we need (rb + c) rather than (rb + b).  The "b" is clearly just a
typo.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>