pckage/ncurses: fix pkg-config files for ncursesw

Currently, ncurses creates symlinks from the non-'w' variants to the
equivalent 'w' variant, but forgets to do so for pkg-config files.

Do that for the pkg-config files too.

Should fix numerous autobuild failures:
    http://autobuild.buildroot.net/results/3c4/3c44dfc6e3f151bef751f39cac336fef3d6a0099/
    http://autobuild.buildroot.net/results/38c/38c81407bb8d0677e87b3a01f9a1fc1372ab4738/


    ...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>