[PATCH] libata: fix class handling in ata_bus_probe()

ata_bus_probe() didn't set classes[] properly for port disabled case
of ->phy_reset() compatibility path.  This patch moves classes[]
initialization and normalization out of ->probe_reset block such that
it applies to both ->probe_reset and ->phy_reset paths.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>