LoongArch: KVM: Add address alignment check for IOCSR emulation

IOCSR instruction supports 1/2/4/8 bytes access, the address should be
naturally aligned with its access size. Here address alignment check is
added in the EIOINTC kernel emulation.

Cc: stable@vger.kernel.org
Fixes: 3956a52b ("LoongArch: KVM: Add EIOINTC read and write functions")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>