qca-wifi: Conditionally define dfs_precac_status_for_channel

When ATH_SUPPORT_ZERO_CAC_DFS is not defined the function
dfs_precac_status_for_channel has 2 definitions, one in dfs_zero_cac.h
and the other in dfs_zero_cac.c.

Fix this by putting the definition in dfs_zero_cac.c under
ATH_SUPPORT_ZERO_CAC_DFS.

Change-Id: I767b7f3bbfe43cb976648c7761cd8e24e4773783

umac/dfs/core/src/misc/dfs_zero_cac.c

@@ -2993,6 +2993,7 @@ dfs_is_precac_completed_count_non_zero(struct wlan_dfs *dfs)
 	return false;
 }
 
+#ifdef ATH_SUPPORT_ZERO_CAC_DFS
 enum precac_status_for_chan
 dfs_precac_status_for_channel(struct wlan_dfs *dfs,
 			      struct dfs_channel *deschan)
@@ -3005,6 +3006,7 @@ dfs_precac_status_for_channel(struct wlan_dfs *dfs,
 
 	return DFS_PRECAC_REQUIRED_CHAN;
 }
+#endif
 
 void dfs_print_precaclists(struct wlan_dfs *dfs)
 {