Lets fix all such races by adding an extra locking to ->set_piomode
and ->set_dmamode methods for PATA controllers.

Would it not be better to take the host lock in libata-core for these
cases so that we fix all the adapters in one swoop. Even if we are doing
this lock taking in the controller specific code it seems the right lock
to use ?

Looks fine as a temproary quickfix tho