sw64: fix deep-copy_user by deep-copy_template

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



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Some fp registers are clobbered in deep-copy_user() because this
function was assumed to be used only in normal task context and to be
safe to clobber caller-save fp registers. However, these assumptions
have been proven wrong.

Since deep-copy_user() is basically a deep-memcpy() with exception
handling, a deep-copy_template() is now used to implement these two
functions. Different macro defines and entry/exit code are used by
deep-copy_user() and deep-memcpy().

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