v850: generic timekeeping conversion

Convert an arch that does not currently implement sub-jiffy timekeeping to
use the generic timekeeping code.

v850 looks like it has some intent to implement sub-jiffy timekeeping, so
it may not yet be appropriate to try to convert, but I figured I'd get the
maintainer's input and submit the patch for comment.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>