psi: update psi irqtime when the irq delta is nozero

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BCV4



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If update psi irqtime whether the irq delta is zero or not, the performance
will be degradation when update_rq_clock_task works frequently.
Therefore, just update psi irqtime whether the irq delta is nozero.
performace test of times:
1) without psi_account_irqtime in update_rq_clock_task
[root@arm64_perf bin]# ./times  -E -C 200 -L -S -W -N "times" -I 200
Running: times# ./../bin-arm64/times -E -C 200 -L -S -W -N times -I 200
             prc thr   usecs/call      samples   errors cnt/samp
times          1   1      0.45210          188        0      500

2) psi_account_irqtime in update_rq_clock_task
[root@arm64_perf bin]# ./times  -E -C 200 -L -S -W -N "times" -I 200
Running: times# ./../bin-arm64/times -E -C 200 -L -S -W -N times -I 200
             prc thr   usecs/call      samples   errors cnt/samp
times          1   1      0.49408          196        0      500

3) psi_account_irqtime in update_rq_clock_task when irq delta is nozero
[root@arm64_perf bin]# ./times  -E -C 200 -L -S -W -N "times" -I 200
Running: times# ./../bin-arm64/times -E -C 200 -L -S -W -N times -I 200
             prc thr   usecs/call      samples   errors cnt/samp
times          1   1      0.45158          195        0      500

Signed-off-by: Lu Jialin <lujialin4@huawei.com>