refactor patch: perf: arm_dsu: Allow IRQ to be shared among devices

[adamliyi]

Original patch: AmpereComputing/ampere-centos-kernel---DEPRECATED@19a1b38

This patch was ported to 5.4 and 5.10 kernel.

In latest ampere-centos-8.0 kernel, in commit: git lab centos-8.0 kernel commit bd56208e48dfd73407eb6e93fecbe023323581b5

This patch has been dropped. We need to refactoring 5.10 and 5.4 kernel.

[adamliyi]

Since FW 1.04.20210129, each dsu is assigned different irq:

# cat /proc/interrupts |  grep -i dsu
169:               GICv3  64 Level     arm_dsu_0
170:               GICv3  65 Level     arm_dsu_1
... ...

So IRQF_SHARED is not necessary.