drm/amdkfd: Fix logic of destroy_queue_nocpsch()

This patch rewrites destroy_queue_nocpsch() as the current logic that is
implemented in the function is completely flawed.

This function is used only in non-HWS mode.

Signed-off-by: Ben Goz <ben.goz@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>