Commit 6e8af08dfa40b747002207d3ce8e8b43a050d99f enables pci=bfsort on
future Dell systems. But the identification string 'Dell System' matches
on already existing whitelist, which do not have SMBIOS type 0xB1,
causing pci=bfsort not being set on existing whitelist.
This patch fixes the regression by moving the type 0xB1 check beyond the
existing whitelist so that existing whitelist is walked before.