ols: Don't #include <libserialport.h> directly.

The driver is not using sp_* calls directly, so no need to #include
the header file.

src/hardware/openbench-logic-sniffer/api.c

@@ -17,7 +17,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <libserialport.h>
 #include "protocol.h"
 
 #define SERIALCOMM "115200/8n1"

src/hardware/openbench-logic-sniffer/protocol.c

@@ -17,7 +17,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <libserialport.h>
 #include "protocol.h"
 
 extern SR_PRIV struct sr_dev_driver ols_driver_info;