drm/amdkfd: add raise exception event function

drm/amdkfd: add raise exception event function

Exception events can be generated from interrupts or queue activitity.

The raise event function will save exception status of a queue, device
or process then notify the debugger of the status change by writing to
a debugger polled file descriptor that the debugger provides during
debug attach.

For memory violation exceptions, extra exception data will be saved.

The debugger will be able to query the saved exception states by query
operation that will be provided by follow up patches.

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>