usb: r8a66597-hcd: Flush the D-cache for the pipe-in transfer buffers.

usb: r8a66597-hcd: Flush the D-cache for the pipe-in transfer buffers.

commit 2717568e7c44fe7dc3f4f52ea823811cfeede2b5 upstream.

This implements the same D-cache flushing logic for r8a66597-hcd as
Catalin's isp1760 (http://patchwork.kernel.org/patch/76391/) change,
with the same note applying here as well:

    When the HDC driver writes the data to the transfer buffers it
    pollutes the D-cache (unlike DMA drivers where the device writes
    the data). If the corresponding pages get mapped into user space,
    there are no additional cache flushing operations performed and
    this causes random user space faults on architectures with
    separate I and D caches (Harvard) or those with aliasing D-cache.

This fixes up crashes during USB boot on SH7724 and others:

	http://marc.info/?l=linux-sh&m=126439837308912&w=2

Reported-by: Goda Yusuke <goda.yusuke@renesas.com>
Tested-by: Goda Yusuke <goda.yusuke@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>