LoongArch: KVM: Add ecode parameter for exception handlers

For some KVM exception types, they share the same exception handler. To
show the difference, ecode (exception code) is added as a new parameter
in exception handlers.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>