Misc timer fixes: - Address a (valid) W=1 build warning - Fix timer self-tests - Annotate a KCSAN warning wrt. accesses to the tick_do_timer_cpu global variable. - Address a !CONFIG_BUG build warning Heads up for the !CONFIG_BUG warning patch, which we addressed with: 5284984a4fba bug: Fix no-return-statement warning with !CONFIG_BUG Not everyone agreed though, see: https://lore.kernel.org/all/20240410153212.127477-1-adrian.hunter@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>