fix: 未充满过，检测到powerdown，最小容量不记录

Signed-off-by: huhui <huhui@sharkgulf.com>

Application/app/sox/soc.c

@@ -235,6 +235,9 @@ static __inline__ float _delta_time(void){
 }
 
 static __inline__ int can_modify_min_cap(void){
+	if (force_full_ts == 0) {
+		return;
+	}
 	if (shark_get_seconds() > force_full_ts){
 		if ((shark_get_seconds() - force_full_ts) > MAX_TIME_FULL_TO_EMPTY) {
 			return 0;