perf c2c report: Add dram related sort keys

They are to be displayed in the main cachelines overall output:

  dram_lcl, dram_rmt

They display DRAM rmt/lcl access numbers for specific cacheline.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-tl3qqi9ehk6g1fla4z7y0ykd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>