suspend/resume handler for radeondrm
suspend/resume handler for radeondrm

All the software state is in the xserver, so all we can do is save
restore the interrupt enable bits (which are expected to persist).

tested by sthen. ok deraadt@.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars