pnv/xive2: Handle TIMA access through all ports

pnv/xive2: Handle TIMA access through all ports

The Thread Interrupt Management Area (TIMA) can be accessed through 4
ports, targeted by the address. The base address of a TIMA
is using port 0 and the other ports are 0x80 apart. Using one port or
another can be useful to balance the load on the snoop buses. With
skiboot and linux, we currently use port 0, but as it tends to be
busy, another hypervisor is using port 1 for TIMA access.

The port address bits fall in between the special op indication
bits (the 2 MSBs) and the register offset bits (the 6 LSBs). They are
"don't care" for the hardware when processing a TIMA operation. This
patch filters out those port address bits so that a TIMA operation can
be triggered using any port.

It is also true for indirect access (through the IC BAR) and it's
actually nothing new, it was already the case on P9. Which helps here,
as the TIMA handling code is common between P9 (xive) and P10 (xive2).

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20230601121331.487207-6-fbarrat@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>