Record acpi_madt_imsic

struct acpi_madt_imsic {
  struct acpi_entry_hdr hdr;
  uacpi_u8 version;
  uacpi_u8 rsvd;
  uacpi_u32 flags;
  uacpi_u16 num_ids;
  uacpi_u16 num_guest_ids;
  uacpi_u8 guest_index_bits;
  uacpi_u8 hart_index_bits;
  uacpi_u8 group_index_bits;
  uacpi_u8 group_index_shift;
  /* Full declaration omitted */ 
}