wlan: Use mem_alloc_copy_from_user_helper() in iw_softap_setwpsie

Function iw_softap_setwpsie() allocates memory and copies user
data using copy_from_user() function.
Replacing these two functions with a common helper function
mem_alloc_copy_from_user_helper().

Change-Id: Iff70c8d55af5db3e8e6cc3728546cd489c608ba1
CRs-Fixed: 681289
diff --git a/CORE/HDD/inc/wlan_hdd_wext.h b/CORE/HDD/inc/wlan_hdd_wext.h
index 30d4023..2a1d52a 100644
--- a/CORE/HDD/inc/wlan_hdd_wext.h
+++ b/CORE/HDD/inc/wlan_hdd_wext.h
@@ -390,6 +390,8 @@
 extern int hdd_priv_get_data(struct iw_point *p_priv_data,
                              union iwreq_data *wrqu);
 
+extern void *mem_alloc_copy_from_user_helper(const void *wrqu_data, size_t len);
+
 void hdd_clearRoamProfileIe( hdd_adapter_t *pAdapter);
 void hdd_GetClassA_statisticsCB(void *pStats, void *pContext);