BugLink: https://bugs.launchpad.net/bugs/1830176

Since commit d5c98ddc "tools include: Adopt linux/bits.h",
the copy of bits.h in tools/include already defines a BIT()
macro.
The re-definition of it in tools/perf/bench/numa.c breaks
the build if enabled. This should go into the master kernel, too
but went undetected because it is not enabled anywhere else.

Fixes: d5c98ddc "tools include: Adopt linux/bits.h"
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>