cns3xxx: use actual size reads for PCIe

cns3xxx: use actual size reads for PCIe

upstream commit 802b7c06adc7 ("ARM: cns3xxx: Convert PCI to use generic config accessors")
reimplemented cns3xxx_pci_read_config() using pci_generic_config_read32(),
which preserved the property of only doing 32-bit reads.

It also replaced cns3xxx_pci_write_config() with pci_generic_config_write(),
so it changed writes from always being 32 bits to being the actual size,
which works just fine.

Due to:
- The documentation does not mention that only 32 bit access is allowed.
- Writes are already executed using the actual size
- Extensive testing shows that 8b, 16b and 32b reads work as intended

It makes perfectly sense to also swap 32 bit reading in favor of actual size.

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>