crypto: hisilicon/qm - fix incorrect parameters usage

In qm_get_xqc_depth(), parameters low_bits and high_bits save
the values of the corresponding bits. However, the values saved by the
two parameters are opposite. As a result, the values returned to the
callers are incorrect.

Fixes: 129a9f34 ("crypto: hisilicon/qm - get qp num and depth from hardware registers")
Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>