regulator: hi6421v600: rename voltage range arrays

regulator: hi6421v600: rename voltage range arrays

The arrays containing the regulator's voltage ranges are
currently named after the first ldo which uses such range.

However, it sounds a lot clearer if those are named with
the voltage range instead.

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/1bdff1d1f23753b69c8044160decfad1e8553d08.1627121912.git.mchehab+huawei@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>