MdeModulePkg/NonDiscoverablePciDev: Fix type mismatch in switch/case
Fix switch/case statement type mismatch in functions PciIoMemRead &
PciIoMemWrite.
Parameter 'Width' is of enum type EFI_PCI_IO_PROTOCOL_WIDTH, but the enum
type provided in 'switch (Width)' block is of type
EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_WIDTH.