ppc/pnv: Add support for PHB5 "Address-based trigger" mode

ppc/pnv: Add support for PHB5 "Address-based trigger" mode

When the Address-Based Interrupt Trigger mode is activated, the PHB
maps the interrupt source number into the interrupt command address.
The PHB directly triggers the IC ESB page of the interrupt number and
not the notify page of the IC anymore.

Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>