[libata] acpi: call ata_acpi_gtm during ata port init time

Commit 30dcf76a mistakenly dropped
the code to get an initial gtm for the IDE channel. This caused the
following problem for Sergei:
http://marc.info/?l=linux-kernel&m=134484963618457&w=2



Fix this by adding the call back in ata_acpi_bind_host, and due to
this, the ata_ap_acpi_handle is modified accordingly.

Tested-by: Sergei Trofimovich <slyich@gmail.com>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>