Use pci_vpd_find_ro_info_keyword() to search for keywords in VPD to
simplify the code.

Link: https://lore.kernel.org/r/f062921c-ad33-3b3e-8ada-b53427a9cd4a@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>