perf annotate: Rename struct annotation_line::samples* to data*

The name 'samples*' is little confusing because we have nested 'struct
sym_hist_entry' under annotation_line struct, which holds 'nr_samples'
as well.

Also the holding struct name is 'annotation_data' so the 'data' name
fits better.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20180804130521.11408-5-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>