sw64: rename dik_* methods

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



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Since die_if_kernel() has been removed, the prefix `dik_` is not
appropriate. Remove this prefix and simplify the implementation
if there is no one to forward the exception to.

Signed-off-by: Wu Liliu <wuliliu@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>