PCI: Remove unnecessary braces

Remove unnecessary braces in pci_bus_distribute_available_resources().  No
functional changes.

Link: https://lore.kernel.org/r/PSXP216MB0438061CB4442460BB92A75F803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM


Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>