modules: hostap: Fix DPP security mode show issue

[Description]
After DUT connects to AP through DPP,
enter 'wifi status' to check connection status.
Security shows UNKNOWN.

[Analysis]
1. DUT supplicant will add a dpp network after
   receiving GAS response.
   Assign ssid->key_mgmt as WPA_KEY_MGMT_DPP.
2. Call wpas_key_mgmt_to_zephyr() to convert
   hostapd/supplicant security type to zephry
   security type.
   In this function, convert WPA_KEY_MGMT_DPP
   to WIFI_SECURITY_TYPE_UNKNOWN.

[Fix]
1. Add code to convert WPA_KEY_MGMT_DPP
   to WIFI_SECURITY_TYPE_DPP.

Signed-off-by: Qiankun Li <qiankun.li@nxp.com>