Self explanatory really. Some newer gcc's print a warning
if a function is used and we don't check its result.
We do this for a bunch of things in the kernel already,
this extends that to the PCI layer.
Based on a patch originally from Arjan van de Ven.
Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>