samples: sockets: added s2868a1 overlay conf files

Added s2868a1 overlay config files at the echo_client and echo_server
samples.

Signed-off-by: Nick Oikonomou <nikoikonomou92@gmail.com>

Author: nikooiko

samples/net/sockets/echo_client/overlay-s2868a1.conf

@@ -0,0 +1,14 @@
+CONFIG_GPIO=y
+CONFIG_SPI=y
+CONFIG_IEEE802154=y
+CONFIG_NET_L2_IEEE802154=y
+CONFIG_NET_L2_IEEE802154_SHELL=y
+CONFIG_NET_IPV4=n
+CONFIG_NET_CONFIG_NEED_IPV4=n
+CONFIG_NET_CONFIG_MY_IPV4_ADDR=""
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR=""
+CONFIG_NET_TCP=n
+CONFIG_IEEE802154_DRIVER_LOG_LEVEL_DBG=y
+CONFIG_NET_CONFIG_IEEE802154_DEV_NAME="IEEE802154_S2LP"
+
+CONFIG_IEEE802154_S2LP=y

samples/net/sockets/echo_client/sample.yaml

@@ -35,3 +35,6 @@ tests:
     extra_args: OVERLAY_CONFIG="overlay-enc28j60.conf"
     tags: net enc28j60
     platform_whitelist: arduino_101
+  sample.net.sockets.echo_client.s2lp:
+    extra_args: OVERLAY_CONFIG="overlay-s2868a1.conf"
+    tags: net

samples/net/sockets/echo_server/overlay-s2868a1.conf

@@ -0,0 +1,14 @@
+CONFIG_GPIO=y
+CONFIG_SPI=y
+CONFIG_IEEE802154=y
+CONFIG_NET_L2_IEEE802154=y
+CONFIG_NET_L2_IEEE802154_SHELL=n
+CONFIG_NET_IPV4=n
+CONFIG_NET_CONFIG_NEED_IPV4=n
+CONFIG_NET_CONFIG_MY_IPV4_ADDR=""
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR=""
+CONFIG_NET_TCP=n
+CONFIG_IEEE802154_DRIVER_LOG_LEVEL_DBG=y
+CONFIG_NET_CONFIG_IEEE802154_DEV_NAME="IEEE802154_S2LP"
+
+CONFIG_IEEE802154_S2LP=y

samples/net/sockets/echo_server/sample.yaml

@@ -64,3 +64,10 @@ tests:
     extra_args: OVERLAY_CONFIG="overlay-smsc911x.conf"
     tags: net
     platform_whitelist: mps2_an385
+  sample.net.sockets.echo_server.smsc911x:
+    extra_args: OVERLAY_CONFIG="overlay-s2868a1.conf"
+    tags: net
+    platform_whitelist: mps2_an385
+  sample.net.sockets.echo_server.s2lp:
+    extra_args: OVERLAY_CONFIG="overlay-s2868a1.conf"
+    tags: net