Make iperf example work with an RM2 breakout board

To use a an RM2 breakout board with a "normal" pico you have to tell
cmake that it supports cyw43 and you have to add the default "pins" to
use to your project.

When building the project pass -DPICO_CYW43_SUPPORTED=1 on the cmake
command line.

cmake -D .. -DPICO_CYW43_SUPPORTED=1

In your project add pin definitions as in this change where WL_ON=2,
CS=3, DAT=4 (in out and wake) and CLK=5. For Pico you seem to have to
slow the pio clock down as well so set div int to 3.

This will only work with the latest SDK 2.1.0.

pico_w/wifi/iperf/CMakeLists.txt

@@ -4,7 +4,16 @@ add_executable(picow_iperf_server_background
 target_compile_definitions(picow_iperf_server_background PRIVATE
         WIFI_SSID=\"${WIFI_SSID}\"
         WIFI_PASSWORD=\"${WIFI_PASSWORD}\"
+
+        CYW43_DEFAULT_PIN_WL_REG_ON=2
+        CYW43_DEFAULT_PIN_WL_CS=3
+        CYW43_DEFAULT_PIN_WL_DATA_OUT=4
+        CYW43_DEFAULT_PIN_WL_DATA_IN=4
+        CYW43_DEFAULT_PIN_WL_HOST_WAKE=4
+        CYW43_DEFAULT_PIN_WL_CLOCK=5
+        CYW43_PIO_CLOCK_DIV_INT=3
         )
+
 target_include_directories(picow_iperf_server_background PRIVATE
         ${CMAKE_CURRENT_LIST_DIR}
         ${CMAKE_CURRENT_LIST_DIR}/.. # for our common lwipopts
@@ -22,6 +31,14 @@ add_executable(picow_iperf_server_poll
 target_compile_definitions(picow_iperf_server_poll PRIVATE
         WIFI_SSID=\"${WIFI_SSID}\"
         WIFI_PASSWORD=\"${WIFI_PASSWORD}\"
+
+        CYW43_DEFAULT_PIN_WL_REG_ON=2
+        CYW43_DEFAULT_PIN_WL_CS=3
+        CYW43_DEFAULT_PIN_WL_DATA_OUT=4
+        CYW43_DEFAULT_PIN_WL_DATA_IN=4
+        CYW43_DEFAULT_PIN_WL_HOST_WAKE=4
+        CYW43_DEFAULT_PIN_WL_CLOCK=5
+        CYW43_PIO_CLOCK_DIV_INT=3
         )
 target_include_directories(picow_iperf_server_poll PRIVATE
         ${CMAKE_CURRENT_LIST_DIR}