AMD DC - Enable new display engine

configname: CONFIG_DRM_AMD_DC

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>Display Engine Configuration
└─>AMD DC - Enable new display engine
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Choose this option if you want to use the new display engine
support for AMDGPU. This adds required support for Vega and
Raven ASICs.

calculate_bandwidth() is presently broken on all !(X86_64 || SPARC64 || ARM64)
architectures built with Clang (all released versions), whereby the stack
frame gets blown up to well over 5k. This would cause an immediate kernel
panic on most architectures. We'll revert this when the following bug report
has been resolved: