ahci: Make ahci_port_base() non-static to enable overwrite

ahci: Make ahci_port_base() non-static to enable overwrite

To allow a board- / platform-specific ahci_port_base() function, this
patch removes "static inline" and adds __weak to this function. This
will be used by the upcoming Armada 7K/8K SATA / AHCI support, which
unfortunately needs a different port base address calculation.

Signed-off-by: Stefan Roese <[email protected]>
Cc: Nadav Haklai <[email protected]>
Cc: Neta Zur Hershkovits <[email protected]>
Cc: Kostya Porotchkin <[email protected]>
Cc: Omri Itach <[email protected]>
Cc: Igal Liberman <[email protected]>
Cc: Haim Boot <[email protected]>
Cc: Hanna Hawa <[email protected]>