Allow D0 to be an input and D1 to be an output, configurable via
platform data and a new DT property.

Based on a patch from  Matus Ujhelyi <matus.ujhelyi@streamunlimited.com>
Signed-off-by: NDaniel Mack <zonque@gmail.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Add device tree support to the OMAP2+ McSPI driver.
Add the bindings documentation.

Based on original code from Rajendra.
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>