perf/core: Simplify the perf_event_alloc() error path

perf/core: Simplify the perf_event_alloc() error path

[ Upstream commit c70ca298036c58a88686ff388d3d367e9d21acf0 ]

The error cleanup sequence in perf_event_alloc() is a subset of the
existing _free_event() function (it must of course be).

Split this out into __free_event() and simplify the error path.

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/20241104135517.967889521@infradead.org
Stable-dep-of: 56799bc03565 ("perf: Fix hang while freeing sigtrap event")
Signed-off-by: Sasha Levin <sashal@kernel.org>