sw64: switch to inline _copy_{to,from}_user()

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PN9S



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Switch to inline version of _copy_{to,from}_user() to improve
performance.

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