minstrel_ht: move minstrel_mcs_groups declaration to header file

Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
Acked-by: NFelix Fietkau <nbd@openwrt.org>

net/mac80211/rc80211_minstrel_ht.h

@@ -29,6 +29,8 @@ struct mcs_group {
 	unsigned int duration[MCS_GROUP_RATES];
 };
 
+extern const struct mcs_group minstrel_mcs_groups[];
+
 struct minstrel_rate_stats {
 	/* current / last sampling period attempts/success counters */
 	unsigned int attempts, last_attempts;

net/mac80211/rc80211_minstrel_ht_debugfs.c

@@ -14,8 +14,6 @@
 #include "rc80211_minstrel.h"
 #include "rc80211_minstrel_ht.h"
 
-extern const struct mcs_group minstrel_mcs_groups[];
-
 static int
 minstrel_ht_stats_open(struct inode *inode, struct file *file)
 {