sw64: remove context check in csum_partial_copy_from_user()

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PNSZ



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This reverts commit ce645515.

In previous patch, we fixed deep-copy_user(). It's now safe to use
it in any context, so no need to check.

Signed-off-by: Mao Minkai <maominkai@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>