uip: Handle the endianess config option correctly.

During one of the config option translation/merge changes earlier, the config
option which determined whether UIP should consider the system to be big or
little endian was broken. The config options are always defined to be 0 or 1
based on whether they're turned on, not defined or not defined. Since it was
always defined, UIP was acting like the host was big endian and not swapping
bytes in some cases.

A more complete fix would be to also switch UIP over to using depthcharge's
endian conversion functions, but that can minimally wait until a later change.

Change-Id: I93c97dad55720c1ff2ab86fa511bbfebc7707dc6
1 file changed