[DEBUG 11/12] drivers: Add two drivers for coherent device memory tests

This adds two different drivers inside drivers/char/ directory under two new kernel config options COHERENT_HOTPLUG_DEMO and COHERENT_MEMORY_DEMO. 1) coherent_hotplug_demo: Detects, hoptlugs the coherent device memory 2) coherent_memory_demo: Exports debugfs interface for VMA migrations

[DEBUG 11/12] drivers: Add two drivers for coherent device memory tests

This adds two different drivers inside drivers/char/ directory under two new kernel config options COHERENT_HOTPLUG_DEMO and COHERENT_MEMORY_DEMO. 1) coherent_hotplug_demo: Detects, hoptlugs the coherent device memory 2) coherent_memory_demo: Exports debugfs interface for VMA migrations