baylibre-acme: Drop unused last_sample_fin variable.

src/hardware/baylibre-acme/protocol.c

@@ -789,6 +789,5 @@ SR_PRIV int bl_acme_receive_data(int fd, int revents, void *cb_data)
 		return TRUE;
 	}
 
-	devc->last_sample_fin = g_get_monotonic_time();
 	return TRUE;
 }

src/hardware/baylibre-acme/protocol.h

@@ -56,7 +56,6 @@ struct dev_context {
 
 	uint32_t num_channels;
 	uint64_t samples_missed;
-	int64_t last_sample_fin;
 	int timer_fd;
 	GIOChannel *channel;
 };