perf: sort-pmuevents: allow for additional type qualifiers and storage class

perf: sort-pmuevents: allow for additional type qualifiers and storage class

With kernel 5.16 some structs in pmu-events do get a const qualifier, some
a static const storage class and qualifier.

The current sort-pmuevents cannot cope with that and drops all struct
arrays with such additional elements. This then leads to compiler errors.

Allow '^struct', '^const struct', '^static struct', '^static const struct'.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>