perf callchain: Fixup parameter handling error message

Fix up parse_callchain_record_opt error message for 'fp', in the past using '-g
fp' was a valid alternative to '--call-graph fp', which is not the case since:

  commit 09b0fd45ff63413df94cbd832a765076b201edbb
  Author: Jiri Olsa <jolsa@redhat.com>
  Date:   Sat Oct 26 16:25:33 2013 +0200

  perf record: Split -g and --call-graph

I.e. -g means "use the configured unwind data collection method" which has as
default 'fp', while --call-graph requires passing the method to use.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1417532814-26208-2-git-send-email-kan.liang@intel.com
[ split this from a larger patch related to LBR based unwinding ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/callchain.c

@@ -77,7 +77,7 @@ int parse_callchain_record_opt(const char *arg)
 				ret = 0;
 			} else
 				pr_err("callchain: No more arguments "
-				       "needed for -g fp\n");
+				       "needed for --call-graph fp\n");
 			break;
 
 #ifdef HAVE_DWARF_UNWIND_SUPPORT