perf c2c: Refactor hist entry validation

perf c2c: Refactor hist entry validation

This patch has no functionality changes but refactors hist entry
validation for cache line resorting.

It renames function "valid_hitm_or_store()" to "is_valid_hist_entry()",
changes return type from integer type to bool type.  In the function,
it uses switch-case instead of ternary operators, which is easier
to extend for more display types.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210114154646.209024-3-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>