arch/aarch64: Allow '0' as valid ISR parameter in interrupt registration

The arch_interrupt_set_isr_irq_param() implementation previously rejected
registration of an interrupt handler if the parameter value was 0. This
prevented valid use cases such as debugger CLI modules which legitimately
use 0 as the callback parameter.

Signed-off-by: Athul P Satheesan <athul.ps@arm.com>