drm/amdkfd: range check cp bad op exception interrupts

Due to a CP interrupt bug, bad packet garbage exception codes are raised.
Do a range check so that the debugger and runtime do not receive garbage
codes.
Update the user api to guard exception code type checking as well.

Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Tested-by: Jesse Zhang <jesse.zhang@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>