sw64: improve deep-copy_template.S

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



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Cache fetch instructions are removed. These instructions will cause more
cache misses and negatively impact performance.

Some unnecessary code alignment are removed to reduce code size.

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