genirq/matrix: Remove unused irq_matrix_alloc_reserved tracepoint

genirq/matrix: Remove unused irq_matrix_alloc_reserved tracepoint

The tracepoint irq_matrix_alloc_reserved was added but never used.
Remove it.

Link: https://lore.kernel.org/all/20250529130138.544ffec4@gandalf.local.home/
Cc: Juergen Gross <jgross@suse.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250529135739.26e5c075@gandalf.local.home
Fixes: ec0f7cd273dc4 ("genirq/matrix: Add tracepoints")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>