mfd: da9052: Fix broken regulator probe

Fix broken probe of da9052 regulators, which since commit b3f6c73d
("mfd: da9052-core: Fix platform-device id collision") use a
non-deterministic platform-device id to retrieve static regulator
information. Fortunately, adequate error handling was in place so probe
would simply fail with an error message.

Update the mfd-cell ids to be zero-based and use those to identify the
cells when probing the regulator devices.

Fixes: b3f6c73d ("mfd: da9052-core: Fix platform-device id collision")
Cc: stable <stable@vger.kernel.org>	# v3.19
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>