fix build (#1395)

diff --git a/src/rp2_common/pico_cyw43_arch/cyw43_arch.c b/src/rp2_common/pico_cyw43_arch/cyw43_arch.c
index 1ee81c7..2408ab8 100644
--- a/src/rp2_common/pico_cyw43_arch/cyw43_arch.c
+++ b/src/rp2_common/pico_cyw43_arch/cyw43_arch.c
@@ -45,7 +45,7 @@
     cyw43_wifi_set_up(&cyw43_state, CYW43_ITF_AP, true, cyw43_arch_get_country_code());
 }
 
-void cyw43_arch_disable_ap_mode() {
+void cyw43_arch_disable_ap_mode(void) {
     assert(cyw43_is_initialized(&cyw43_state));
     cyw43_wifi_set_up(&cyw43_state, CYW43_ITF_AP, false, cyw43_arch_get_country_code());
 }
diff --git a/src/rp2_common/pico_cyw43_arch/include/pico/cyw43_arch.h b/src/rp2_common/pico_cyw43_arch/include/pico/cyw43_arch.h
index a8af5da..32476bb 100644
--- a/src/rp2_common/pico_cyw43_arch/include/pico/cyw43_arch.h
+++ b/src/rp2_common/pico_cyw43_arch/include/pico/cyw43_arch.h
@@ -375,7 +375,7 @@
  *
  * This Disbles the Wi-Fi in \em Access \em Point mode.
  */
-void cyw43_arch_disable_ap_mode();
+void cyw43_arch_disable_ap_mode(void);
 
 /*!
  * \brief Attempt to connect to a wireless access point, blocking until the network is joined or a failure is detected.