package/kmsxx: fix static install

Currently, we only try to install the shared libraries.

However, when doing a static build, only the static libs are built,
obviously.

Fix this by only installing relevant libraries.

Fixes:
    http://autobuild.buildroot.org/results/82c/82cfb7451f933b222abe30b5d35d23e409a4af79/
    http://autobuild.buildroot.org/results/bb3/bb3840f14382b6ed77d5947eb3ac5c229286681e/



Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>