The GPIO block on different QorIQ chips could have registers in different
endianess.  Define the property to specify which endian is used by the
hardware.
Signed-off-by: NLiu Gang <Gang.Liu@freescale.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NLi Yang <leoli@freescale.com>
Signed-off-by: NKevin Hilman <khilman@linaro.org>