regulator: Move OF-specific regulator lookup code to of_regulator.c

regulator: Move OF-specific regulator lookup code to of_regulator.c

There's still a bit of OF-specific code in the regulator device lookup
function.

Move those bits of code over to of_regulator.c, and create a new
function of_regulator_dev_lookup() to encapsulate the code moved out of
regulator_dev_lookup().

Also mark of_find_regulator_by_node() as static, since there are no
other users in other compile units.

There are no functional changes. A line alignment was also fixed.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240904090016.2841572-4-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>