staging: fsl-mc/dpio: Use __leXX types where needed

Structures that are mapped to hardware registers should explicitly
specify the expected endianness for fields larger than 1 byte.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>