fix to use only transceiver_pid from transceiver.c

drivers/cc110x_ng/cc110x.c

@@ -40,8 +40,6 @@ volatile uint8_t radio_state = RADIO_UNKNOWN;       ///< Radio state
 static radio_address_t radio_address;                     ///< Radio address
 static uint8_t radio_channel;                             ///< Radio channel
 
-int transceiver_pid;                         ///< the transceiver thread pid
-
 /* internal function prototypes */
 static int rd_set_mode(int mode);
 static void reset(void);

drivers/include/cc110x_ng/cc110x-interface.h

@@ -115,7 +115,7 @@ extern volatile uint8_t rx_buffer_next;     ///< Next packet in RX queue
 extern volatile uint8_t radio_state;        ///< Radio state
 extern cc110x_statistic_t cc110x_statistic;
 
-int transceiver_pid;                         ///< the transceiver thread pid
+extern int transceiver_pid;                         ///< the transceiver thread pid
 
 void cc110x_init(int transceiver_pid);