staging: fsl-mc/dpio: Skip endianness conversion in portal config

Writing to the register using writel does the CPU to LE conversion down the
line, so it's not required here. Doing it breaks portal configuration on
big endian kernels.

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>