PCI: cadence: Drop excess cdns_pcie_rc.dev kerneldoc description

Struct cdns_pcie_rc once had a .dev member, but it was removed by
bd22885a ("PCI: cadence: Refactor driver to use as a core library").
Drop the extra kerneldoc for it.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/cadence/pcie-cadence.h

@@ -314,7 +314,6 @@ struct cdns_pcie {
 /**
  * struct cdns_pcie_rc - private data for this PCIe Root Complex driver
  * @pcie: Cadence PCIe controller
- * @dev: pointer to PCIe device
  * @cfg_res: start/end offsets in the physical system memory to map PCI
  *           configuration space accesses
  * @cfg_base: IO mapped window to access the PCI configuration space of a