hwmon: (adm1177) simplify using devm_regulator_get_enable()

Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
add_action_or_reset(regulator_disable)' and use the
devm_regulator_get_enable() and drop the pointer to the regulator.
This simplifies code and makes it less tempting to add manual control
for the regulator which is also controlled by devm.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/7773541795f280db31dd981ffc21df8a630b794a.1666357434.git.mazziesaccount@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>