mac802154: remove unused macro

This patch removes the unused macro which was removed
with the rework of linux-wpan kernel.

Signed-off-by: Varka Bhadram <varkab@cdac.in>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index 6d4f3cc..ed87463 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -94,8 +94,6 @@
 	struct mac802154_llsec sec;
 };
 
-#define MAC802154_CHAN_NONE		0xff /* No channel is assigned */
-
 /* utility functions/constants */
 extern const void *const mac802154_wpan_phy_privid; /*  for wpan_phy privid */