pci_cap
pci_add_capability(uint8_t id, struct pci_cap *cap)
dev->pd_caps[cid - 1].pc_next = (sizeof(struct pci_cap) * cid) +
int pci_add_capability(uint8_t, struct pci_cap *);
struct pci_cap pd_caps[PCI_MAX_CAPS];
struct pci_cap pci;