media: lirc: revert removal of unused feature flags

Commit b2a90f4f ("media: lirc: remove unused lirc features") removed
feature flags which were never implemented, but they are still used by
the lirc daemon went built from source.

Reinstate these symbols in order not to break the lirc build.

Fixes: b2a90f4f ("media: lirc: remove unused lirc features")
Link: https://lore.kernel.org/all/a0470450-ecfd-2918-e04a-7b57c1fd7694@kernel.org/Reported-by: Jiri Slaby <jirislaby@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/uapi/linux/lirc.h

@@ -84,6 +84,13 @@
 #define LIRC_CAN_SEND(x) ((x)&LIRC_CAN_SEND_MASK)
 #define LIRC_CAN_REC(x) ((x)&LIRC_CAN_REC_MASK)
 
+/*
+ * Unused features. These features were never implemented, in tree or
+ * out of tree. These definitions are here so not to break the lircd build.
+ */
+#define LIRC_CAN_SET_REC_FILTER		0
+#define LIRC_CAN_NOTIFY_DECODE		0
+
 /*** IOCTL commands for lirc driver ***/
 
 #define LIRC_GET_FEATURES              _IOR('i', 0x00000000, __u32)