Revert "ata: ahci_platform: allow disabling of hotplug to save power"

This reverts commit aece27a2.

Causes boot failure on some devices.

 http://lore.kernel.org/r/CA+G9fYuKW_jCFZPqG4tz=QY9ROfHO38KiCp9XTA+KaDOFVtcqQ@mail.gmail.com



Signed-off-by: Tejun Heo <tj@kernel.org>