perf inject: Remove static variables

perf inject: Remove static variables

We want to reduce the impact that each of the builtins has on perf as a
whole, so use the superclassing of perf_tool mechanizm to move its
config knobs to the stack, so that only if we use that tool, its impact
will be felt.

In this case is more about consistency, as the impact of this tool is
minimal.

Cc: David Ahern <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>