Move buildroot to bsp directory.

bsp/buildroot/package/systemd/network.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=Network Connectivity
+Wants=network.target
+Before=network.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+
+# lo is brought up earlier, which will cause the upcoming "ifup -a" to fail
+# with exit code 1, due to an "ip: RTNETLINK answers: File exists" error during
+# its "ip addr add ..." command, subsequently causing this unit to fail even
+# though it is a benign error. Flushing the lo address with the command below
+# before ifup prevents this failure.
+ExecStart=/sbin/ip addr flush dev lo
+
+ExecStart=/sbin/ifup -a
+ExecStop=/sbin/ifdown -a
+
+[Install]
+WantedBy=multi-user.target