hw/intc/aspeed: Introduce IRQ handler function to reduce code duplication

hw/intc/aspeed: Introduce IRQ handler function to reduce code duplication

The behavior of the INTC set IRQ is almost identical between INTC and INTCIO.
To reduce duplicated code, introduce the "aspeed_intc_set_irq_handler" function
to handle both INTC and INTCIO IRQ behavior. No functional change.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250307035945.3698802-16-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>