PCI: aardvark: Size bridges before resources allocation

The PCIE I/O and MEM resource allocation mechanism is that root bus
goes through the following steps:

1. Check PCI bridges' range and computes I/O and Mem base/limits.

2. Sort all subordinate devices I/O and MEM resource requirements and
   allocate the resources and writes/updates subordinate devices'
   requirements to PCI bridges I/O and Mem MEM/limits registers.

Currently, PCI Aardvark driver only handles the second step and lacks
the first step, so there is an I/O and MEM resource allocation failure
when using a PCI switch. This commit fixes that by sizing bridges
before doing the resource allocation.

Fixes: 8c39d710 ("PCI: aardvark: Add Aardvark PCI host controller
driver")
Signed-off-by: Zachary Zhang <zhangzg@marvell.com>
[Thomas: edit commit log.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: <stable@vger.kernel.org>