samples/net sntp_client: Replace deprecated option

CONFIG_ETH_NATIVE_POSIX is deprecated in favor of
CONFIG_ETH_NATIVE_TAP, let's replace it.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

samples/net/sockets/sntp_client/overlay-nsos.conf

@@ -1,6 +1,6 @@
 # Copyright (c) 2025 Embeint Inc
 
-CONFIG_ETH_NATIVE_POSIX=n
+CONFIG_ETH_NATIVE_TAP=n
 CONFIG_NET_DRIVERS=y
 CONFIG_NET_SOCKETS=y
 CONFIG_NET_SOCKETS_OFFLOAD=y