Increase BTLE output power

Default is -10 dBm

I've played around and here are a few hints:

+extern int8_t tx_rfpower_on;
 void MacInit(void)
 {
     wsfHandlerId_t handlerId;
@@ -203,6 +204,12 @@ void MacInit(void)
     LlConnSlaveInit();
     handlerId = WsfOsSetNextHandler(LlHandler);
     LlHandlerInit(handlerId);
+    printf("tx_rfpower_on = %d\n", tx_rfpower_on);
+    HciVsSetTxPower(10);
+    //HciVsSetTxPower(-30);
+    //tx_rfpower_on = 10;
+    //LlSetTxPower(10);
+    printf("tx_rfpower_on = %d\n", tx_rfpower_on);
 }

I think the chip should be able to output 10 dBm, but I only got it to 0 dBm