crypto: hisilicon/qm - set NULL to qm->debug.qm_diff_regs

When the initialization of qm->debug.acc_diff_reg fails,
the probe process does not exit. However, after qm->debug.qm_diff_regs is
freed, it is not set to NULL. This can lead to a double free when the
remove process attempts to free it again. Therefore, qm->debug.qm_diff_regs
should be set to NULL after it is freed.

Fixes: 8be0913 ("crypto: hisilicon/debugfs - Fix debugfs uninit process issue")
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: Chenghai Huang

drivers/crypto/hisilicon/debugfs.c

@@ -888,6 +888,7 @@ static int qm_diff_regs_init(struct hisi_qm *qm,
 		dfx_regs_uninit(qm, qm->debug.qm_diff_regs, ARRAY_SIZE(qm_diff_regs));
 		ret = PTR_ERR(qm->debug.acc_diff_regs);
 		qm->debug.acc_diff_regs = NULL;
+		qm->debug.qm_diff_regs = NULL;
 		return ret;
 	}