usb: renesas_usbhs: add DMAEngine ID specification note
usb: renesas_usbhs: add DMAEngine ID specification note

renesas_usbhs DMAEngine uses D0FIFO/D1FIFO,
but the data transfer direction should be fixed for keeping consistency.
This patch explain about it on renesas_usbhs.h

Signed-off-by: Kuninori Morimoto <a3b51ccb87d18302c1692defcfbf83319d1737eb@renesas.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas