perf evsel: Move evsel__* functions to evsel.c

perf evsel: Move evsel__* functions to evsel.c

At least one of these were put here to avoid a Python binding linking
issue which is no longer present. Put them back in their correct
location to avoid confusion about which file to add a new evsel__*
function to later.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/all/ZEbAS2yx2fguW60w@kernel.org/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>