Add regulator supply into PWBUS_REGULATOR macro. This makes it optional
to define a vin-supply in DT. Not defining a supply will add a dummy
regulator supply instead and only cause the following debug output:
```
Looking up vin-supply property in node [...] failed
```
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Link: https://lore.kernel.org/r/58f2ff7b90233fad3d7ae2e9d66d5192e2c1ac01.1645437439.git.sylv@sylv.io
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
#define PMBUS_REGULATOR(_name, _id) \
[_id] = { \
.name = (_name # _id), \
+ .supply_name = "vin", \
.id = (_id), \
.of_match = of_match_ptr(_name # _id), \
.regulators_node = of_match_ptr("regulators"), \