random: Fix kabi change of get_random_bytes()

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BB


CVE: NA

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Commit 07280d2c3f33 ("random: make more consistent use of integer types")
change the type of parameter nbytes from int to size_t, which break kabi
compatibility.
Separately revert the relate modifications of get_random_bytes() to fix
kabi change.

Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: GUO Zihua <guozihua@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>