slcand: include <sys/socket.h>

Linux build compiles without errors, but Android build
complains about undefined routines and macros.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

slcand.c

@@ -28,6 +28,7 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/socket.h>
 #include <fcntl.h>
 #include <syslog.h>
 #include <errno.h>