ppc/pnv: quad xscom callbacks are P9 specific

Rename the functions to include P9 in the name in preparation for adding
P10 versions.

Correct the unimp read message while we're changing the function.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Message-ID: <20230704054204.168547-2-joel@jms.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
1 file changed