perf tools: Missing c2c command in command-list

Add the c2c command to command-list.txt so perf help can list this
command.

Committer notes:

Before:

  # perf help | grep c2c
  #

After:

  # perf help | grep c2c
     c2c             Shared Data C2C/HITM Analyzer.
  #
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170313082845.23373-1-changbin.du@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/command-list.txt

@@ -9,6 +9,7 @@ perf-buildid-cache		mainporcelain common
 perf-buildid-list		mainporcelain common
 perf-data			mainporcelain common
 perf-diff			mainporcelain common
+perf-c2c			mainporcelain common
 perf-config			mainporcelain common
 perf-evlist			mainporcelain common
 perf-ftrace			mainporcelain common