hw/intc/aplic: refine the APLIC realize

hw/intc/aplic: refine the APLIC realize

When the APLIC is emulated in the kernel, the GPIO output lines to CPUs
can be remove. In this case the APLIC trigger CPU interrupts by KVM APIs.

This patch also move the code that claim the CPU interrupts to the
beginning of APLIC realization. This can avoid the unnecessary resource
allocation before checking failed.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20250224025722.3999-3-yongxuan.wang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>