perf/arm-cmn: Fix the unhandled overflow status of counter 4 to 7

perf/arm-cmn: Fix the unhandled overflow status of counter 4 to 7

The register por_dt_pmovsr Bits[7:0] indicates overflow from counters 7
to 0. But in arm_cmn_handle_irq(), only handled the overflow status of
Bits[3:0] which results in unhandled overflow status of counters 4 to 7.

So let the overflow status of DTC counters 4 to 7 to be handled.

Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver")
Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/1695612152-123633-1-git-send-email-renyu.zj@linux.alibaba.com
Signed-off-by: Will Deacon <will@kernel.org>