PCI: Simplify if-return sequences

Simplify a trivial if-return sequence.  Possibly combine with a preceding
function call.

Generated by: scripts/coccinelle/misc/simple_return.cocci

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>