remove useless check as previous one is enough

src/main.c

@@ -122,7 +122,6 @@ void read_can(Tel *t, int soc) {
 
         if (nbytes != sizeof(struct can_frame)) return;
 
-        if (nbytes > 0) {
 
         switch (frame.can_id) {
 
@@ -135,7 +134,6 @@ void read_can(Tel *t, int soc) {
                         break;
         }
 }
-}
 
 void read_uart(Tel *t, int fd, SerialParser *uart_str) {
         char buf[128];