usb: dwc2: host: Get aligned DMA in a more supported way

All other host controllers who want aligned buffers for DMA do it a
certain way.  Let's do that too instead of working behind the USB core's
back.  This makes our interrupt handler not take forever and also rips
out a lot of code, simplifying things a bunch.

This also has the side effect of removing the 65535 max transfer size
limit.

NOTE: The actual code to allocate the aligned buffers is ripped almost
completely from the tegra EHCI driver.  At some point in the future we
may want to add this functionality to the USB core to share more code
everywhere.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: John Youn <johnyoun@synopsys.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: John Youn <johnyoun@synopsys.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>