ata: ahci: Add Tiger Lake UP{3,4} AHCI controller

Mark the Tiger Lake UP{3,4} AHCI controller as "low_power". This enables
S0ix to work out of the box. Otherwise this isn't working unless the
user manually sets /sys/class/scsi_host/*/link_power_management_policy.

Intel lists a total of 4 SATA controller IDs in [1] for those mobile
PCHs. This commit just adds the "AHCI" variant since I only tested
those.

[1]: https://cdrdv2.intel.com/v1/dl/getContent/631119

Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com>
CC: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>