misc/far2l: fix build on big-endian architectures

Looks like there are now 2 copies of 7z to be fixed:
far2l-2.7.0_1.log:/wrkdirs/usr/ports/misc/far2l/work/far2l-v_2.7.0/arclite/src/7z/h/C/CpuArch.h:280:4: error: Stop_Compiling_Bad_Endian