usb: mtu3: add memory barrier before set GPD's HWO

stable inclusion
from stable-v5.10.90
commit f10b01c48f856d5fc11fbef271e1bd9abcdf0f0d
bugzilla: 186168 https://gitee.com/openeuler/kernel/issues/I4SHY1

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f10b01c48f856d5fc11fbef271e1bd9abcdf0f0d



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commit a7aae769 upstream.

There is a seldom issue that the controller access invalid address
and trigger devapc or emimpu violation. That is due to memory access
is out of order and cause gpd data is not correct.
Add mb() to prohibit compiler or cpu from reordering to make sure GPD
is fully written before setting its HWO.

Fixes: 48e0d373 ("usb: mtu3: supports new QMU format")
Cc: stable@vger.kernel.org
Reported-by: Eddie Hung <eddie.hung@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20211218095749.6250-2-chunfeng.yun@mediatek.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>