Tidy clang build warnings

- Remove transceiver enums from hackrf.h
 - convert uint64_ts to int64_ts for frequency maths

host/libhackrf/src/hackrf.c

@@ -78,6 +78,8 @@ typedef enum {
 	HACKRF_TRANSCEIVER_MODE_OFF = 0,
 	HACKRF_TRANSCEIVER_MODE_RECEIVE = 1,
 	HACKRF_TRANSCEIVER_MODE_TRANSMIT = 2,
+	HACKRF_TRANSCEIVER_MODE_SS = 3,
+	TRANSCEIVER_MODE_CPLD_UPDATE = 4,
 } hackrf_transceiver_mode;
 
 struct hackrf_device {