drm/amdkfd: Enforce kill all waves on process termination

This commit makes sure that on process termination, after
we're destroying all the active queues, we're killing all the
existing wave front of the current process.

By doing this we're making sure that if any of the CUs were blocked
by infinite loop we're enforcing it to end the shader explicitly.

Signed-off-by: Ben Goz <ben.goz@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>