crypto: hisilicon/qm - move the barrier before writing to the mailbox register

crypto: hisilicon/qm - move the barrier before writing to the mailbox register

Before sending the data via the mailbox to the hardware, to ensure
that the data accessed by the hardware is the most up-to-date,
a write barrier should be added before writing to the mailbox register.
The current memory barrier is placed after writing to the register,
the barrier order should be modified to be before writing to the register.

Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>