LoongArch: fix signal handler name changed

LoongArch inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6MUZX



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commit ad404010 ("entry: Add support for TIF_NOTIFY_SIGNAL")
changed then signal handler name from arch_do_signal to
arch_do_signal_or_restart,change the signal handler name for LoongArch
accordingly.

Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>