LoongArch: fix SECCOMP test error

LoongArch inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6BWFP



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When we test the ltp testcase prctl04,we get failed.The reason is
_TIF_SECOMP not defined for LoongArch.So define the _TIF_SECCOMP
for LoongArch.

Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Change-Id: I6e890cf347839f301b45036693a0cce3736d3ce3
(cherry picked from commit b8690293)