lib: Update to latest can2040 code

Clear PIO irq flags in pio_sm_setup()
Set TXPENDING during pio_sm_setup()

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

lib/can2040/can2040.c

@@ -347,6 +347,8 @@ pio_sm_setup(struct can2040 *cd)
     pio_hw_t *pio_hw = cd->pio_hw;
     pio_hw->ctrl = PIO_CTRL_SM_RESTART_BITS | PIO_CTRL_CLKDIV_RESTART_BITS;
     pio_hw->fdebug = 0xffffffff;
+    pio_hw->irq = 0xff;
+    pio_signal_set_txpending(cd);
 
     // Load pio program
     int i;