pci: Fix register for determining type of IO base address

Function dm_pciauto_prescan_setup_bridge() configures base address
registers, therefore it should read type of IO from base address registers
(and not from limit address registers).

Note that base and limit address registers should have same type, so this
change is just usage correction and has no functional change on correctly
working hardware.

Fixes: 8e85f36a ("pci: Fix configuring io/memory base and limit registers of PCI bridges")
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>