fix(parlio): fix rempty interrupt during resetting fifo

Move the fifo reset to after disabling the tx core clock.
And add external non-free running clock src test.

components/hal/esp32c6/include/hal/parlio_ll.h

@@ -373,6 +373,7 @@ static inline void parlio_ll_rx_update_config(parl_io_dev_t *dev)
  * @param dev Parallel IO register base address
  * @param src Clock source
  */
+__attribute__((always_inline))
 static inline void parlio_ll_tx_set_clock_source(parl_io_dev_t *dev, parlio_clock_source_t src)
 {
     (void)dev;