drm/amdkfd: Add wave control operation to debugger

The wave control operation supports several command types executed upon
existing wave fronts that belong to the currently debugged process.

The available commands are:

HALT   - Freeze wave front(s) execution
RESUME - Resume freezed wave front(s) execution
KILL   - Kill existing wave front(s)

Signed-off-by: Yair Shachar <yair.shachar@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>