With the root hub unbinding in usb_stop(), there is no need to do
a Sandbox-specific reset operation. usb_emul_reset() is no longer
used anywhere, drop it.
Change-Id: I07087b328686bcf0020a938fcd4ea8ac74396b9b
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
(cherry picked from commit ad56e4b684a97565cdce15c28df1ccff9032d594)