luafilesystem: Correctly handle usrmerge
Fixes the recipe to correctly install when the usrmerge DISTRO_FEATURE
is active. In this case, base_libdir=/usr/lib, so it should not be
specified as an argument. Also correctly use the ${prefix} variable for
the install prefix
Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Joshua Watt <Joshua.Watt@garmin.com>