buildroot

package/libmad: don't install .pc in target

We explicitly remove pkg-config files from target in the target-finalize
step, and our pkg-config looks for .pc files from staging, not target.

So, explicitly installing the .pc in target is useless.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>