enable optimal defaults on linux kernels that can support newer features.

src/switch_core.c

@@ -1662,9 +1662,6 @@ static void switch_load_core_config(const char *file)
 					switch_time_set_monotonic(switch_true(val));
 				} else if (!strcasecmp(var, "enable-softtimer-timerfd")) {
 					switch_time_set_timerfd(switch_true(val));
-					if (switch_true(val)) {
-						switch_clear_flag((&runtime), SCF_CALIBRATE_CLOCK);
-					}
 				} else if (!strcasecmp(var, "enable-clock-nanosleep")) {
 					switch_time_set_nanosleep(switch_true(val));
 				} else if (!strcasecmp(var, "enable-cond-yield")) {