perf/x86/intel: Reorganize attrs and is_visible

Some attrs and is_visible implementations are rather far away from one
another which makes the whole thing hard to interpret.

There are only two attribute groups which have both .attrs and
.is_visible, group_default and group_caps_lbr. Move them together.

No functional changes.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20231025201626.3000228-4-kan.liang@linux.intel.com