Unused parameter warning in async_context_freertos.c

[earlephilhower]

While not an error, async_context_freertos_wait_until has an unused parameter:

/home/earle/Arduino/hardware/pico/rp2040/libraries/FreeRTOS/src/../../../pico-sdk/src/rp2_common/pico_async_context/async_context_freertos.c: In function 'async_context_freertos_wait_until':
/home/earle/Arduino/hardware/pico/rp2040/libraries/FreeRTOS/src/../../../pico-sdk/src/rp2_common/pico_async_context/async_context_freertos.c:265:64: warning: unused parameter 'self_base' [-Wunused-parameter]
  265 | static void async_context_freertos_wait_until(async_context_t *self_base, absolute_time_t until) {
      |                                               ~~~~~~~~~~~~~~~~~^~~~~~~~~

[kilograham]

merged into develop