coresight: trbe: Add a helper to calculate the trace generated

mainline inclusion
from mainline-v5.15-rc3
commit 41c0e5b7
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5YCYK
CVE: NA

Reference: https://lore.kernel.org/r/20211019163153.3692640-6-suzuki.poulose@arm.com



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We collect the trace from the TRBE on FILL event from IRQ context
and via update_buffer(), when the event is stopped. Let us
consolidate how we calculate the trace generated into a helper.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-6-suzuki.poulose@arm.com


Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>