hwmon: (pmbus/pxe1610) don't bail out when not all pages are active

[ Upstream commit f0253143 ]

Certain VRs might be configured to use only the first output channel and
so the mode for the second will be 0. Handle this gracefully.

Fixes: b9fa0a3a ("hwmon: (pmbus/core) Add support for vid mode detection per page bases")
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Link: https://lore.kernel.org/r/20210416102926.13614-1-fercerpav@gmail.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>