The AK8975 has two power sources: Vdd (analog voltage supply)
and Vid (digital voltage supply). Optionally also obtain the Vid
supply regulator and enable it.
If an error occurs when enabling one of the regulators: bail out.
Cc: Gregor Boirie <gregor.boirie@parrot.com> Cc: Richard Leitner <dev@g0hl1n.net> Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com> Cc: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>