Allow to use a switch-case instead of an array holding ISR entries.
When most of IRQs are not used, they share the same, default entry.
It results in most of the ISR array entries being identical duplicates.
This change allows to use dynamically generated function (after first
linker pass) that uses switch-case instead of a full array.
Default entries are handled only once, in a default section.
Used IRQs have their own case sections.
This can help reduce binary size.
Signed-off-by: Adam Szczygieł <adam.szczygiel@nordicsemi.no>
f4747547d9