pciutils: SHARED make opt goes for install too

If we don't pass SHARED when installing we miss the shared library
symlinks (libpci.so & libpci.so.3).

On internal and external toolchains that have a proper cross ldconfig this
isn't a problem as they get created during ldconfig, but it breaks on
toolchains that lack a cross ldconfig to automagically make the symlinks.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>