LoongArch: KVM: Remove unused returns and semicolons

The default branch has already handled all undefined cases, so the final
return statement is redundant. Redundant semicolons are removed, too.

Cc: stable@vger.kernel.org
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>

arch/loongarch/kvm/exit.c

@@ -718,10 +718,8 @@ static long kvm_save_notify(struct kvm_vcpu *vcpu)
 		return 0;
 	default:
 		return KVM_HCALL_INVALID_CODE;
-	};
-
-	return KVM_HCALL_INVALID_CODE;
-};
+	}
+}
 
 /*
  * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.