I have verified HDLC with QorIQ SDK 2.0 1703 images on LS1021ATWR, it worked normally, please refer to the following procedure.
Please configure Linux Kernel as the following.
Device Drivers --->
SOC (System On Chip) specific Drivers --->
[*] Freescale QUICC Engine (QE) Support
[*] Network device support --->
[*] Wan interfaces support --->
<*> Generic HDLC layer
<*> Raw HDLC support
<*> Freescale QUICC Engine HDLC support
On the target board:
root@ls1021atwr:~# ./sethdlc hdlc0 hdlc
root@ls1021atwr:~# ifconfig hdlc0 192.168.0.1 up
hdlc0: Carrier detected
root@ls1021atwr:~# ./sethdlc hdlc0
hdlc0: interface e1 clock type unknown slotmap 10101010010001011111010000000001
protocol hdlc nrz crc16-itu
root@ls1021atwr:~#
The attached are uImage, ls1021a-twr.dtb and sethdlc, you could use them to do verification on your target board.