net: sockets: add support for select() when using socket offloading
net: sockets: add support for select() when using socket offloading

When socket offloading is used, we should build the implementation of
select().

Fixes #12705

Signed-off-by: Vincent Wan <7ae6840d3573b56510a1ea731789ea8c898aa415@ti.com>

finikorg/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr