qcacmn: Remove static from nla_policy btc_chain_mode_policy

Remove static from nla_policy btc_chain_mode_policy in correspondence to
the change to add policy attribute to BTC_CHAIN_MODE vendor subcommand.

Change-Id: Ie33542199d27f6b9d8ea5e0a1a063b71ecb7fd94
CRs-Fixed: 2635059

os_if/linux/coex/inc/wlan_cfg80211_coex.h

@@ -23,6 +23,10 @@
 #include <wlan_cfg80211.h>
 #include <wlan_objmgr_cmn.h>
 
+extern const struct nla_policy
+	btc_chain_mode_policy
+	[QCA_VENDOR_ATTR_BTC_CHAIN_MODE_MAX + 1];
+
 #ifdef FEATURE_COEX
 int wlan_cfg80211_coex_set_btc_chain_mode(struct wlan_objmgr_vdev *vdev,
 					  const void *data, int data_len);