crypto: hisilicon/qm - cleanup warning in qm_vf_read_qos

The kernel test rebot report this warning: Uninitialized variable: ret.
The code flow may return value of ret directly. This value is an
uninitialized variable, here is fix it.

Signed-off-by: Kai Ye <yekai13@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>