x86/PCI: Simplify Dell DMI B1 quirk

No need for such convoluted code, when all we need is to call one function
in one specific case.

Tested-by: Narendra K <Narendra.K@dell.com> # DellEMC PowerEdge 1950, R730XD
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>