SDHCI driver for Tegra. This driver plugs in as a new variant of
sdhci-pltfm, using the platform data structure passed in to specify the
GPIOs to use for card detect, write protect and card power enablement.

Original driver (of which only the header file is left):
Signed-off-by: NYvonne Yip <y@palm.com>

The rest, which has been rewritten by now:
Signed-off-by: NOlof Johansson <olof@lixom.net>
Reviewed-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NMike Rapoport <mike@compulab.co.il>
Signed-off-by: NChris Ball <cjb@laptop.org>