We need to refactor code to be explicitely shared by the kernel and at
least the tools/ userspace programs, so, till we do that, copy the bare
minimum bitmap/bitops code needed by tools/perf.

Reported-by: "H. Peter Anvin"
Cc: Frédéric Weisbecker
Cc: Mike Galbraith
Cc: Paul Mackerras
Cc: Peter Zijlstra
LKML-Reference:
Signed-off-by: Arnaldo Carvalho de Melo