dyndbg: combine flags & mask into a struct, simplify with it

flags & mask are used together everywhere, and are passed around
together between multiple functions; they belong together in a struct,
call that struct flag_settings.

Use struct flag_settings to rework 3 functions:
 - ddebug_exec_query - declares query and flag-settings,
   		     calls other 2, passing flags
 - ddebug_parse_flags - fills flag_settings and returns
 - ddebug_change - test all callsites against query,
   		   modify passing sites.

benefits:
 - bit-banging always needs flags & mask, best together.
 - simpler function signatures
 - 1 less parameter, less stack overhead

no functional changes

Acked-by:  <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200719231058.1586423-16-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>