drivers: wifi: winc1500: remove unused send_cb and send_user_data
drivers: wifi: winc1500: remove unused send_cb and send_user_data

Both 'cb' and 'user_data' parameters for send/sendto were saved as
'send_cb' and 'send_user_data' members in socket information. None of
them are actually used, so drop them.

Signed-off-by: Marcin Niestroj <63506c06cfbc47ace147db1702f6e751f5ac2132@grinn-global.com>

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