perf sched: Add --input=file option to builtin-sched.c

perf sched record passes unparsed args on to perf record, so
specifying an output file via perf sched record -o FILE (cmd) just
works.  Ergo, provide an option to specify input file as well.

Also add the missing 'map' command to help.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1253254944.20589.11.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>