pci: xilinx: Fix doc comments on config space accessors

These take the 'struct udevice *' as an argument, not the
'struct xilinx_pcie *` which is a local variable. Fix the comments to
match the code.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

drivers/pci/pcie_xilinx.c

@@ -87,7 +87,7 @@ static int pcie_xilinx_config_address(struct xilinx_pcie *pcie, pci_dev_t bdf,
 
 /**
  * pcie_xilinx_read_config() - Read from configuration space
- * @pcie: Pointer to the PCI controller state
+ * @bus: Pointer to the PCI bus
  * @bdf: Identifies the PCIe device to access
  * @offset: The offset into the device's configuration space
  * @valuep: A pointer at which to store the read value
@@ -130,7 +130,7 @@ static int pcie_xilinx_read_config(struct udevice *bus, pci_dev_t bdf,
 
 /**
  * pcie_xilinx_write_config() - Write to configuration space
- * @pcie: Pointer to the PCI controller state
+ * @bus: Pointer to the PCI bus
  * @bdf: Identifies the PCIe device to access
  * @offset: The offset into the device's configuration space
  * @value: The value to write