PCI: mobiveil: Fix devfn check in mobiveil_pcie_valid_device()

Current check for devfn number in mobiveil_pci_valid_device() is
wrong in that it flags as invalid functions present in PCI device 0
in the root bus while it is perfectly valid to access all functions
in PCI device 0 in the root bus.

Update the check in mobiveil_pci_valid_device() to fix the issue.

Fixes: 9af6bcb11e12 ("PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver")
Signed-off-by: Hou Zhiqiang <[e-mail]>
Signed-off-by: Lorenzo Pieralisi <[e-mail]>
Reviewed-by: Minghuan Lian <[e-mail]>

drivers/pci/controller/pcie-mobiveil.c

···
 	 * Do not read more than one device on the bus directly
 	 * attached to RC
 	 */
-	if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
+	if ((bus->primary == pcie->root_bus_nr) && (PCI_SLOT(devfn) > 0))
 		return false;
 
 	return true;