rtl8188eu: Fix a possible sleep-in-atomic bug in rtw_createbss_cmd

The driver may sleep under a spinlock, and the function call path is:
rtw_surveydone_event_callback(acquire the spinlock)
  rtw_createbss_cmd
    kzalloc(GFP_KERNEL) --> may sleep

To fix it, GFP_KERNEL is replaced with GFP_ATOMIC.
This bug is found by my static analysis tool and my code review.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/core/rtw_cmd.c

@@ -333,7 +333,7 @@ u8 rtw_createbss_cmd(struct adapter  *padapter)
 	else
 		RT_TRACE(_module_rtl871x_cmd_c_, _drv_info_, (" createbss for SSid:%s\n", pmlmepriv->assoc_ssid.Ssid));
 
-	pcmd = kzalloc(sizeof(struct cmd_obj), GFP_KERNEL);
+	pcmd = kzalloc(sizeof(struct cmd_obj), GFP_ATOMIC);
 	if (!pcmd) {
 		res = _FAIL;
 		goto exit;