gen_isr_tables: Function ptr instead of (void *)
gen_isr_tables: Function ptr instead of (void *)

gen_isr_tables.py generates C-code which initializes a table with
values, and these values are structs with members cast to
(const void *) and (void *), respectively.

The actual struct definition has a member of type (const void *)
and another of type void (*)(const void *).

In order to avoid a large amount of reported issues in Coverity,
cast this to the exact type.

Signed-off-by: Torstein Grindvik <6be8892e8e25f53d87bea9b6c9499480fb2e1f2d@nordicsemi.no>

finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,nashif/zephyr,finikorg/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr