Curious gpio_clr_mask/gpio_set_mask statements

[neuschaefer]

First of all, thank you for publishing Pico-PIO-USB!

pio_usb_device.c contains a few gpio_*_mask statements that were introduced in commit ef9d780. Specifically:

128:  gpio_clr_mask(1<<3);
138:      gpio_set_mask(1 << 3);
202:  gpio_clr_mask(1<<4);

These statements look like debug statements that were left in the code by accident; In projects that use GPIO 3/4, I think they might cause issues.

Do these lines still serve a purpose?