PCI: aardvark: Introduce an advk_pcie_valid_device() helper

In other to mimic other PCIe host controller drivers, introduce an
advk_pcie_valid_device() helper, used in the configuration read/write
functions.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[lorenzo.pieralisi@arm.com: updated host->controller dir move]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/controller/pci-aardvark.c

@@ -433,6 +433,15 @@ static int advk_pcie_wait_pio(struct advk_pcie *pcie)
 	return -ETIMEDOUT;
 }
 
+static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus,
+				  int devfn)
+{
+	if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0)
+		return false;
+
+	return true;
+}
+
 static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 			     int where, int size, u32 *val)
 {
@@ -440,7 +449,7 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 	u32 reg;
 	int ret;
 
-	if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0) {
+	if (!advk_pcie_valid_device(pcie, bus, devfn)) {
 		*val = 0xffffffff;
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
@@ -494,7 +503,7 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
 	int offset;
 	int ret;
 
-	if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0)
+	if (!advk_pcie_valid_device(pcie, bus, devfn))
 		return PCIBIOS_DEVICE_NOT_FOUND;
 
 	if (where % size)