qcacmn: Fix driver crash observed during AFC request processing

Currently the AFC request buffer is being freed twice in
reg_free_expiry_afc_info and tgt_afc_event_handler.
Make changes to free the AFC req buffer only once.

Change-Id: I6d0f5c783a124da40eae6166132f7d7132cf76e4

umac/regulatory/core/src/reg_build_chan_list.c

@@ -2378,7 +2378,6 @@ static void reg_disable_afc_mas_chan_list_channels(
 static void reg_free_expiry_afc_info(struct afc_regulatory_info *afc_info)
 {
 	qdf_mem_free(afc_info->expiry_info);
-	qdf_mem_free(afc_info);
 }
 
 /**