tracing, AER: Hide PCIe AER event when PCIEAER is not configured

tracing, AER: Hide PCIe AER event when PCIEAER is not configured

The event aer_event is only used when CONFIG_PCIEAER is configured. It
should not be created when it is not. When an event is created it creates
around 5K of text and meta data regardless if the tracepoint is used or
not. Instead of wasting this memory, put #ifdef around the event to not
create it when it is not used.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250612094932.4a08abd6@batman.local.home
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>