drm/amdkfd: add events IOCTL set definitions

- AMDKFD_IOC_CREATE_EVENT:
	Creates a new event of a specified type

- AMDKFD_IOC_DESTROY_EVENT:
	Destroys an existing event

- AMDKFD_IOC_SET_EVENT:
	Signal an existing event

- AMDKFD_IOC_RESET_EVENT:
	Reset an existing event

- AMDKFD_IOC_WAIT_EVENTS:
	Wait on event(s) until they are signaled

v2:

- Move the limit of the signal events to kfd_ioctl.h so it
  can be used by userspace

v3:
- Change all bool fields in struct kfd_memory_exception_failure
to uint32_t

Signed-off-by: Andrew Lewycky <Andrew.Lewycky@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>