sw64: remove unused code for unaligned load store emulation

Sunway inclusion
category: performance
bugzilla: https://gitee.com/openeuler/kernel/issues/I56OLG



--------------------------------

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