usb: dwc2: host: Always add to the tail of queues

The queues the the dwc2 host controller used are truly queues.  That
means FIFO or first in first out.

Unfortunately though the code was iterating through these queues
starting from the head, some places in the code was adding things to the
queue by adding at the head instead of the tail.  That means last in
first out.  Doh.

Go through and just always add to the tail.

Doing this makes things much happier when I've got:
* 7-port USB 2.0 Single-TT hub
* - Microsoft 2.4 GHz Transceiver v7.0 dongle
* - Jabra speakerphone playing music

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