Fix unused parameter warning.

[martinbudden]

Fixes issue #2662.

Adds (void)transfer_count; for parameter transfer_count to avoid warning.

[lurch]

Would it be "better" to use the __unused attribute, e.g. https://github.com/raspberrypi/pico-sdk/blob/develop/src/rp2_common/hardware_dma/include/hardware/dma.h#L59 ?

[martinbudden]

I'm not familiar with the __unused attribute. Do you mean?

static inline uint32_t dma_encode_transfer_count_with_self_trigger(uint transfer_count) {
#if PICO_RP2040
    __unused transfer_count;
    panic_unsupported();
#else
    return dma_encode_transfer_count(transfer_count) | (DMA_CH0_TRANS_COUNT_MODE_VALUE_TRIGGER_SELF << DMA_CH0_TRANS_COUNT_MODE_LSB);
#endif
}

Since transfer_count is only unused in the PICO_RP2040 build.

Or do you mean

static inline uint32_t dma_encode_transfer_count_with_self_trigger(__unused uint transfer_count) {

Either way, I'll happily update the PR.

[lurch]

I'm not super-familiar either, I just remember seeing it used a lot of times (e.g. see the line that I linked to).
Perhaps @will-v-pi or @kilograham will be able to confirm the preferred style in pico-sdk. (I suspect they're just different ways of doing the same thing?)

[martinbudden]

I've also seen (void) used in the code. As you say, it's just a question of confirming the prefered style.