perf/core: Introduce perf_free_addr_filters()

Replace _free_event()'s use of perf_addr_filters_splice()s use with an
explicit perf_free_addr_filters() with the explicit propery that it is
able to be called a second time without ill effect.

Most notable, referencing event->pmu must be avoided when there are no
filters left (from eg a previous call).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20241104135518.868460518@infradead.org