video: Change composite_sync default value to 1

* Change default composite_sync value to 1

From a troubleshooting perspective, composite_sync=1 seems like a more common gotcha because more people are using consumer CRTs than monitors.

I'm wondering if it makes sense to make this change as it covers more use cases.

* Update cfg.cpp

cfg.cpp

@@ -574,6 +574,7 @@ const char* cfg_get_label(uint8_t alt)
 void cfg_parse()
 {
 	memset(&cfg, 0, sizeof(cfg));
+	cfg.composite_sync = 1;
 	cfg.bootscreen = 1;
 	cfg.fb_terminal = 1;
 	cfg.controller_info = 6;