non-default device IDs and udev rules

[jacobmgn]

aws-fpga/hdk/cl/examples/cl_dram_dma_hlx/README.md

Line 51 in 4750aac

set ::env(device_id) "0xF001"

Related to: #560

Users that uses a non-default device ID are not informed in the README that they should also add their device ID to the udev rule to allow non-root access