random: update comment from copy_to_user() -> copy_to_iter()

stable inclusion
from stable-v5.10.127
commit feb5ab798698a05d14e74804dd09ba352c714553
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5XDDK

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=feb5ab798698a05d14e74804dd09ba352c714553



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commit 63b8ea5e upstream.

This comment wasn't updated when we moved from read() to read_iter(), so
this patch makes the trivial fix.

Fixes: 1b388e77 ("random: convert to using fops->read_iter()")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>