RFC: ARM HLCD: Add support for HDLCD device driver

Hello,

This is an initial attempt to add support for ARM's HDLCD device into
the mainline kernel. This code has been in use by Linaro for a while
and now it's time to push it into mainline as more people will have
access to the CoreTiles that support the device.

This patch is sent as an RFC as I am new to the whole submission
process in the kernel and would like to gather feedback first.

Thanks,
Liviu