This patch is to add the general hardware last level cache (LLC) events
for PMUv3: one event is for LLC access and another is for LLC miss.

With this change, perf tool can support last level cache profiling,
below is an example to demonstrate the usage on Arm64:

  $ perf stat -e LLC-load-misses -e LLC-loads -- \
	  perf bench mem memcpy -s 1024MB -l 100 -f default

  [...]

    Performance counter stats for 'perf bench mem memcpy -s 1024MB -l 100 -f default':

        35,534,262      LLC-load-misses           #    2.16% of all LL-cache hits
     1,643,946,443      LLC-loads

  [...]
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Link: https://lore.kernel.org/r/20200811053505.21223-1-leo.yan@linaro.orgSigned-off-by: Will Deacon <will@kernel.org>