crypto: hisilicon/trng - fix local variable type

mainline inclusion
from mainline-master
commit 00856e53
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5MK7S
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=00856e5391fb



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The return value of 'readl_poll_timeout' is '0' or '-ETIMEDOUT'. Therefore,
change the local variable 'ret' type from 'u32' to 'int'.

Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jiangshui Yang <yangjiangshui@h-partners.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>