userswap: add checks for input addresses

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6CAIM



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Add checks for new_addr in uswap_mremap() and src_addr in
uswap_check_copy_mode(), including user mode checks, overlapping
checks, etc.

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>