drm/amdkfd: add per process hw trap enable and disable functions

drm/amdkfd: add per process hw trap enable and disable functions

To enable HW debug mode per process, all devices must be debug enabled
successfully.  If a failure occures, rewind the enablement of debug mode
on the enabled devices.

A power management scenario that needs to be considered is HW
debug mode setting during GFXOFF.  During GFXOFF, these registers
will be unreachable so we have to transiently disable GFXOFF when
setting.  Also, some devices don't support the RLC save restore
function for these debug registers so we have to disable GFXOFF
completely during a debug session.

Cooperative launch also has debugging restriction based on HW/FW bugs.
If such bugs exists, the debugger cannot attach to a process that uses GWS
resources nor can GWS resources be requested if a process is being
debugged.

Multi-process debug devices can only enable trap temporaries based
on certain runtime scenerios, which will be explained when the
runtime enable functions are implemented in a follow up patch.

Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>