luajit: pass correct libdir

When build luajit-native:
/buildarea2/build/tmp/sysroots/x86_64-linux/usr ====
| rmdir: failed to remove '/buildarea2/build/tmp/work/x86_64-linux/luajit-native/2.0.3-r0/image/buildarea2/build/tmp/sysroots/x86_64-linux/usr/lib/lua/5.*': No such file or directory
| rmdir: failed to remove '/buildarea2/build/tmp/work/x86_64-linux/luajit-native/2.0.3-r0/image/buildarea2/build/tmp/sysroots/x86_64-linux/usr/lib/lua': No such file or directory
| WARNING: exit code 1 from a shell command.

Use ${baselib} instead of ${base_libdir} for variable MULTILIB in
Makefile. Otherwise the INSTALL_LIB would extend to wrong path.

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>