media: lirc: remove unused feature LIRC_CAN_SET_REC_DUTY_CYCLE

There is no hardware which can filter input on the duty cycle, so no
driver implements this. On top of that, LIRC_CAN_SET_REC_DUTY_CYCLE
has the same value as LIRC_CAN_MEASURE_CARRIER (0x02000000).
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Documentation/userspace-api/media/lirc.h.rst.exceptions

@@ -30,7 +30,6 @@ ignore define LIRC_CAN_REC
 
 ignore define LIRC_CAN_SEND_MASK
 ignore define LIRC_CAN_REC_MASK
-ignore define LIRC_CAN_SET_REC_DUTY_CYCLE
 
 # Obsolete ioctls
 

include/uapi/linux/lirc.h

@@ -73,7 +73,6 @@
 #define LIRC_CAN_REC_MASK              LIRC_MODE2REC(LIRC_CAN_SEND_MASK)
 
 #define LIRC_CAN_SET_REC_CARRIER       (LIRC_CAN_SET_SEND_CARRIER << 16)
-#define LIRC_CAN_SET_REC_DUTY_CYCLE    (LIRC_CAN_SET_SEND_DUTY_CYCLE << 16)
 
 #define LIRC_CAN_SET_REC_CARRIER_RANGE    0x80000000
 #define LIRC_CAN_GET_REC_RESOLUTION       0x20000000