[media] nuvoton-cir: carrier detect support is broken - remove it

The carrier detect return value is never used on nuvoton driver:
drivers/media/rc/nuvoton-cir.c: In function 'nvt_process_rx_ir_data':
drivers/media/rc/nuvoton-cir.c:623:6: warning: variable 'carrier' set but not used [-Wunused-but-set-variable]
Also, this would be called only if a boolean variable is enabled,
but there's no condition that enables it inside the driver. So,
comment the carrier detection code, as it might be useful later,
and remove the unused glue code.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/rc/nuvoton-cir.c

@@ -472,6 +472,7 @@ static void nvt_enable_wake(struct nvt_dev *nvt)
 	nvt_cir_wake_reg_write(nvt, 0, CIR_WAKE_IREN);
 }
 
+#if 0 /* Currently unused */
 /* rx carrier detect only works in learning mode, must be called w/nvt_lock */
 static u32 nvt_rx_carrier_detect(struct nvt_dev *nvt)
 {
@@ -504,7 +505,7 @@ static u32 nvt_rx_carrier_detect(struct nvt_dev *nvt)
 
 	return carrier;
 }
-
+#endif
 /*
  * set carrier frequency
  *
@@ -620,7 +621,6 @@ static void nvt_dump_rx_buf(struct nvt_dev *nvt)
 static void nvt_process_rx_ir_data(struct nvt_dev *nvt)
 {
 	DEFINE_IR_RAW_EVENT(rawir);
-	u32 carrier;
 	u8 sample;
 	int i;
 
@@ -629,9 +629,6 @@ static void nvt_process_rx_ir_data(struct nvt_dev *nvt)
 	if (debug)
 		nvt_dump_rx_buf(nvt);
 
-	if (nvt->carrier_detect_enabled)
-		carrier = nvt_rx_carrier_detect(nvt);
-
 	nvt_dbg_verbose("Processing buffer of len %d", nvt->pkts);
 
 	init_ir_raw_event(&rawir);

drivers/media/rc/nuvoton-cir.h

@@ -103,7 +103,6 @@ struct nvt_dev {
 
 	/* rx settings */
 	bool learning_enabled;
-	bool carrier_detect_enabled;
 
 	/* track cir wake state */
 	u8 wake_state;