dm: pmic: Split output from function

The regulator_autoset() function mixes printf() output and PMIC adjustment
code. It provides a boolean to control the output. It is better to avoid
missing logic and output, and this permits a smaller SPL code size. So
split the output into a separate function.

Also rename the function to have a by_name() suffix, since we would like
to be able to pass a device when we know it, and thus avoid the name
search.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Przemyslaw Marczak <p.marczak@samsung.com>