Refactor pmbus_is_enabled() to return the status without any additional
processing as it is already done in _pmbus_is_enabled().

Fixes: df5f6b6a ("hwmon: (pmbus/core) Generalise pmbus get status")
Cc: stable@vger.kernel.org # v6.4
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20230725125428.3966803-1-Naresh.Solanki@9elements.com
[groeck: Rephrased commit message]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>