MFC r308186, r308188, r308231, r308232:

MFC r308186, r308188, r308231, r308232:

  Move imx_sdhci driver over to a dev/sdhci in preparation for QorIQ support.
  Freescale uses eSDHC in both i.MX (ARM) and QorIQ (PowerPC), with slight
  differences.  This is part one in unifying the drivers.

  Merge i.MX and PowerPC SDHCI drivers
  Summary:
  i.MX5 and PowerPC use a very similar eSDHC controller, which is also
  similar to the uSDHC controller used by i.MX6.  The imx_sdhci driver works
  almost completely with PowerPC, with some minor tweaks.

  Fix the build.  protctl is only used on powerpc.
  While here, remove the need to check the SVR SPR, as others may be compatible
  with the p1022-esdhc type.

  Since it's no longer accessing a powerpc-specific register, drop the #ifdef.