ARM: 6608/1: enable bridges in pci_common_init.

Add a missing call to pci_enable_bridges() so that devices behind
bridges get found by the pci bus scan.

Signed-off-by: Chris Partington <chris.partington@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>