fix(lwip): fix "unistd.h" I/O APIs not declare when disable VFS
When enable VFS, apps code should include "unistd.h", "sys/ioctl.h" or "fcntl.h" if using "read", "write", "close", "ioctl" and "fcntl".
#include "sdkconfig.h"
#include "lwip/sockets.h"
+
+#if !LWIP_POSIX_SOCKETS_IO_NAMES
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#endif /* !LWIP_POSIX_SOCKETS_IO_NAMES */
