usb: renesas_usbhs: Fix fifo unclear in usbhsf_prepare_pop

This patch fixes an issue for control write. When usbhsf_prepare_pop()
is called after this driver called a gadget setup function, this controller
doesn't receive the control write data. So, this patch adds a code to clear
the fifo for control write in usbhsf_prepare_pop().

Signed-off-by: Kazuya Mizuguchi <[e-mail]>
Signed-off-by: Yoshihiro Shimoda <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/renesas_usbhs/fifo.c

···
 static int usbhsf_prepare_pop(struct usbhs_pkt *pkt, int *is_done)
 {
 	struct usbhs_pipe *pipe = pkt->pipe;
+	struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
+	struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv);
 
 	if (usbhs_pipe_is_busy(pipe))
 		return 0;
···
 	 */
 	usbhs_pipe_data_sequence(pipe, pkt->sequence);
 	pkt->sequence = -1; /* -1 sequence will be ignored */
+
+	if (usbhs_pipe_is_dcp(pipe))
+		usbhsf_fifo_clear(pipe, fifo);
 
 	usbhs_pipe_set_trans_count_if_bulk(pipe, pkt->length);
 	usbhs_pipe_enable(pipe);