usb: renesas_usbhs: expand USB-DMAC channels for R-Car Gen2

This patch expands USB-DMAC channels for R-Car Gen2 SoCs. The SoCs
have 4 channels. If d{2,3}_{t,x}x_id are not set, this driver never
uses the expanded USB-DMAC channels.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/renesas_usbhs/fifo.h b/drivers/usb/renesas_usbhs/fifo.h
index 899729a..f07037c1 100644
--- a/drivers/usb/renesas_usbhs/fifo.h
+++ b/drivers/usb/renesas_usbhs/fifo.h
@@ -38,7 +38,7 @@
 	struct sh_dmae_slave	rx_slave;
 };
 
-#define USBHS_MAX_NUM_DFIFO	2
+#define USBHS_MAX_NUM_DFIFO	4
 struct usbhs_fifo_info {
 	struct usbhs_fifo cfifo;
 	struct usbhs_fifo dfifo[USBHS_MAX_NUM_DFIFO];