MdeModulePkg/NonDiscoverablePciDeviceDxe: Add comments for functions

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.h

@@ -102,6 +102,12 @@ typedef struct {
   LIST_ENTRY                UncachedAllocationList;
 } NON_DISCOVERABLE_PCI_DEVICE;
 
+/**
+  Initialize PciIo Protocol.
+
+  @param  Device      Point to NON_DISCOVERABLE_PCI_DEVICE instance.
+
+**/
 VOID
 InitializePciIoProtocol (
   NON_DISCOVERABLE_PCI_DEVICE     *Device