About LC_CMD_FPGA_BAR_FUNCTION_CALLBACK deadlock.

[maoxian123]

When set LC_CMD_FPGA_BAR_FUNCTION_CALLBACK,it works fine at first,after few mins,it will freeze,the bar read will return 0xff,and no enter the callback.
I check the DeviceFPGA_Tlp_Callback_ThreadProc is not exit.