Add CDC+UAC2 composite device example for Pico

Signed-off-by: Dhiru Kholia <dhiru.kholia@gmail.com>

examples/device/cdc_uac2/CMakeLists.txt

@@ -0,0 +1,38 @@
+cmake_minimum_required(VERSION 3.17)
+
+include(${CMAKE_CURRENT_SOURCE_DIR}/../../../hw/bsp/family_support.cmake)
+
+# gets PROJECT name for the example (e.g. <BOARD>-<DIR_NAME>)
+family_get_project_name(PROJECT ${CMAKE_CURRENT_LIST_DIR})
+
+project(${PROJECT} C CXX ASM)
+
+# Checks this example is valid for the family and initializes the project
+family_initialize_project(${PROJECT} ${CMAKE_CURRENT_LIST_DIR})
+
+# Espressif has its own cmake build system
+if(FAMILY STREQUAL "espressif")
+  return()
+endif()
+
+add_executable(${PROJECT})
+
+# Example source
+target_sources(${PROJECT} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/main.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/tusb_cdc.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/tusb_uac2.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/usb_descriptors.c
+        )
+
+# Example include
+target_include_directories(${PROJECT} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src
+        )
+
+# Configure compilation flags and libraries for the example... see the corresponding function
+# in hw/bsp/FAMILY/family.cmake for details.
+family_configure_device_example(${PROJECT})
+
+# Uncomment me to enable UART based debugging
+# pico_enable_stdio_uart(${PROJECT} 1)