Documentation: dyndbg: Improve cli param examples

Documentation: dyndbg: Improve cli param examples

Jim pointed out that using $module.dyndbg= is always a more flexible
choice for using dynamic debug on the command line. The $module.dyndbg
style is checked at boot and handles if $module is a builtin. If it is
actually a loadable module, it is handled again later when the module is
loaded.

If you just use dyndbg="module $module +p" dynamic debug is only enabled
when $module is a builtin.

It was recommended to illustrate wildcard usage as well.

Suggested-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Link: https://lore.kernel.org/r/1634139622-20667-4-git-send-email-jbaron@akamai.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>