pata_hpt366: remove redundant code

There's no need to clear the fast interrupt bit in hpt366_set_mode()
since we're doing it in hpt366_init_chipset() already.

While at it, rename 'addr1' local variable to 'addr' and
exclude 'ap->port_no' from its calculation as HPT36x are
single-channel-per-function chips.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>