This is a follow-up patch based on the review for perfmon2.  This patch
adds the carta_random32() library routine + carta_random32.h header file.

This is fast, simple, and efficient pseudo number generator algorithm.  We
use it in perfmon2 to randomize the sampling periods.  In this context, we
do not need any fancy randomizer.
Signed-off-by: Nstephane eranian <eranian@hpl.hp.com>
Cc: David Mosberger <david.mosberger@acm.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>