hwmon: (mlxreg-fan) Fix macros for tacho fault reading

Fix macros for tacometer fault reading.
This fix is relevant for three Mellanox systems MQMB7, MSN37, MSN34,
which are about to be released to the customers.
At the moment, none of them is at customers sites.

Fixes: 65afb4c8 ("hwmon: (mlxreg-fan) Add support for Mellanox FAN driver")
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>