tracing: Use vmalloc_array() to improve code

Remove array_size() calls and replace vmalloc() with vmalloc_array() in
tracing_map_sort_entries().  vmalloc_array() is optimized better, uses
fewer instructions, and handles overflow more concisely[1].

[1]: https://lore.kernel.org/lkml/abc66ec5-85a4-47e1-9759-2f60ab111971@vivo.com/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250817084725.59477-1-rongqianfeng@vivo.com


Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>