Fix percentile_list option

Commit 802ad4a8 broke the parsing of the percentile list,
by neglecting to change the parser type fo a fio_fp64_t.

Also get rid of the def_percentile_list, just set the
default percentile list as the option default.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/stat.c b/stat.c
index 62eee9a..fb5ff64 100644
--- a/stat.c
+++ b/stat.c
@@ -1210,10 +1210,7 @@
 		ts = &threadstats[j];
 
 		ts->clat_percentiles = td->o.clat_percentiles;
-		if (td->o.overwrite_plist)
-			memcpy(ts->percentile_list, td->o.percentile_list, sizeof(td->o.percentile_list));
-		else
-			memcpy(ts->percentile_list, def_percentile_list, sizeof(def_percentile_list));
+		memcpy(ts->percentile_list, td->o.percentile_list, sizeof(td->o.percentile_list));
 
 		idx++;
 		ts->members++;