target/riscv: update APLIC and IMSIC to support KVM AIA

KVM AIA can't emulate APLIC only. When "aia=aplic" parameter is passed,
APLIC devices is emulated by QEMU. For "aia=aplic-imsic", remove the
mmio operations of APLIC when using KVM AIA and send wired interrupt
signal via KVM_IRQ_LINE API.
After KVM AIA enabled, MSI messages are delivered by KVM_SIGNAL_MSI API
when the IMSICs receive mmio write requests.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Jim Shu <jim.shu@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-ID: <20230727102439.22554-5-yongxuan.wang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>