Add a simple PIO based host controller for MMC and SD cards
on PXA SoCs. Reads and writes are available, and no usage is
made of DMA or IRQs.
SPI mode is not supported yet.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
