perf bench mem: Rename 'routine' to 'routine_str'

perf bench mem: Rename 'routine' to 'routine_str'

So bench/mem-functions.c has a 'routine' name for the routines parameter
string, but a 'length_str' name for the length parameter string.

We also have another entity named 'routine': 'struct routine'.

This is inconsistent and confusing: rename 'routine' to 'routine_str'.

Also fix typos in the --routine help text.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1445241870-24854-9-git-send-email-mingo@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>