Cadhu have multiple power rails which are controlled by
GPIOs. Add support of these power rail control through
fixed regulators. Add entry for all fixed regulators for
cardhu-a02 and a04.
The details are taken from downstream kernel.

Some points on this change are:

* Add the tps65910-LDO5 entry and make it always ON
 to supply power to SDMMC. Once the sd driver support
 regulator handling, this flag will be remove.

* Dropping registration of rail vdd_sdmmc1 as the gpio
  is used by sdhci power-gpio. This need to fix in
  sdhci driver and then need to add the registration
  mechanism. Just removing power-gpio and adding fixed
  regulator with this gpio is causing the sd  access to
  fail because first probe call of this regulator fails
  due to non-available of parent and so it calls
  gpio_free() which disable the pins in gpio mode make
  pin output to LOW causes power to OFF. In probe retry,
  it got success and it powered-on but it again need to
  do again numeration of card here.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>