cmake: cleanup newlib CMakeLists.txt file

Commit 282f77e732f0a4bc859f559bc5a748f953a8140c removed the only place
defining LIBC_INCLUDE_DIR. Remove the corresponding use of
LIBC_INCLUDE_DIR from newlib/CMakeLists.txt as this setting is no longer
being defined anywhere.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
1 file changed