add hostname option in dhcp discover
add hostname option in dhcp discover

    Hostname option has been removed from dhcp discover since IDFv3.2.
But it remains in dhcp request due to which ESP32 can not get IPv4 address
from some APs. Re-add hostname option to dhcp discover to solve this issue.

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf