While cross compiling, if the dir of "$(rootlibdir)" and "$(libdir)"
(such as "/usr/lib64") do not exist on host system, the do_instal failed.
-----------------------
make[3]: Entering directory `tmp/work/core2-64-wrs-linux/ntfs-3g-ntfsprogs/2017.3.23-r0/build/libntfs-3g'
if [ ! "/usr/lib64" -ef "/usr/lib64" ]; then \
    mv -f "tmp/work/core2-64-wrs-linux/ntfs-3g-ntfsprogs/2017.3.23-r0/image//usr/lib64"/libntfs-3g.so* \
        "tmp/work/core2-64-wrs-linux/ntfs-3g-ntfsprogs/2017.3.23-r0/image//usr/lib64";  \
fi
mv:...are the same file
-----------------------

Use `=' rather than `-ef' to compare them, the cross compile does not
care about host dir.

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>