block: ahci: Don't enable port interrupts

This patch changes the initialization of the AHCI controller to not
enable the default interrupts (DEF_PORT_IRQ). As interrupts are
not used in U-Boot in general, this should not break the common AHCI
driver operation.

This change is needed to support the Marvell Armada 38x AHCI
controller. With interrupts enabled, this results in timeouts in
ahci_device_data_io(). Not enabling these interrupts fixes this
problem and the common AHCI driver works fine.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Luka Perkov <luka.perkov@sartura.hr>