regulator: add IPQ4019 SDHCI VQMMC LDO driver

This introduces the IPQ4019 VQMMC LDO driver needed for
the SD/EMMC driver I/O level operation.
This will enable introducing SD/EMMC support for the built-in controller.

Signed-off-by: Mantas Pucka <mantas@8devices.com>
Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Link: https://lore.kernel.org/r/20200112113003.11110-1-robert.marko@sartura.hr


Signed-off-by: Mark Brown <broonie@kernel.org>