ata: ahci_platform: Increase AHCI_MAX_CLKS to 4

The Tegra124 SATA controller requires 4 clocks. Increase this constant
to be able to use them all.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>