regulator: stpmic1: Add static const qualifier at peroper places

The regulator_linear_range arrays and stpmic1_regulator_cfgs are only
accessed by this driver and the values are never changed so make them
static const. regulator_ops variables can also be const.
Also clean up a few empty lines in regulator_linear_range array.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>