The vhub engine has two dma mode, one is descriptor list, another
is single stage DMA. Each mode has different stop register setting.
Descriptor list operation (bit2) : 0 disable reset, 1: enable reset
Single mode operation (bit0) : 0 : disable, 1: enable

Fixes: 7ecca2a4 ("usb/gadget: Add driver for Aspeed SoC virtual hub")
Cc: stable <stable@vger.kernel.org>
Acked-by: Felipe Balbi <balbi@kernel.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
Link: https://lore.kernel.org/r/20210108081238.10199-2-ryan_chen@aspeedtech.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>