lib/route/cls/u32.c: use UCHAR_MAX define instead of numeric 255
lib/route/cls/u32.c: use UCHAR_MAX define instead of numeric 255

tklauser/libnl,tklauser/libnl,thom311/libnl,greearb/libnl-ct,greearb/libnl-ct,thom311/libnl,thom311/libnl,tklauser/libnl,greearb/libnl-ct,tklauser/libnl