tracing: samples: Initialize trace_array_printk() with the correct function

tracing: samples: Initialize trace_array_printk() with the correct function

When using trace_array_printk() on a created instance, the correct
function to use to initialize it is:

  trace_array_init_printk()

Not

  trace_printk_init_buffer()

The former is a proper function to use, the latter is for initializing
trace_printk() and causes the NOTICE banner to be displayed.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Divya Indi <divya.indi@oracle.com>
Link: https://lore.kernel.org/20250509152657.0f6744d9@gandalf.local.home
Fixes: 89ed42495ef4a ("tracing: Sample module to demonstrate kernel access to Ftrace instances.")
Fixes: 38ce2a9e33db6 ("tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>