usb: renesas_usbhs: add support for USB-DMAC

Some Renesas SoCs have the USB-DMAC. It is able to terminate transfers
when a short packet is received, even if less bytes than the transfer
counter size have been received. Also, it is able to send a short
packet even if the packet size is not multiples of 8bytes.

Since the previous code has used the interruption of USBHS controller
when receiving packets even if this driver has used a dmac, a lot of
interruptions has happened. This patch will reduce such interruptions.

This patch allows to use the USB-DMAC on R-Car H2 and M2.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

include/linux/usb/renesas_usbhs.h

@@ -165,6 +165,8 @@ struct renesas_usbhs_driver_param {
 	 */
 	u32 has_otg:1; /* for controlling PWEN/EXTLP */
 	u32 has_sudmac:1; /* for SUDMAC */
+	u32 has_usb_dmac:1; /* for USB-DMAC */
+#define USBHS_USB_DMAC_XFER_SIZE	32	/* hardcode the xfer size */
 };
 
 #define USBHS_TYPE_R8A7790 1