MdeModulePkg RamDiskDxe: Uninstall DEVICE_PATH_PROTOCOL with correct param

Previously, the code uninstalls the DEVICE_PATH_PROTOCOL with the device
path given by caller of the 'RamDiskUnregister' function. The given device
path might be different from the one used to install the
DEVICE_PATH_PROTOCOL.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskProtocol.c

@@ -324,7 +324,7 @@ RamDiskUnregister (
                &gEfiBlockIo2ProtocolGuid,
                &PrivateData->BlockIo2,
                &gEfiDevicePathProtocolGuid,
-               DevicePath,
+               (EFI_DEVICE_PATH_PROTOCOL *) PrivateData->DevicePath,
                NULL
                );