ARM: sa1100: Convert PCI to use generic config accessors

Convert the sa1100 nanoengine PCI driver to use the generic config access
functions.

Change accesses from __raw_readX/__raw_writeX to readX/writeX variants.
This removes the spinlock because it is unnecessary.  The config read and
write functions are already protected with a spinlock.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: linux-arm-kernel@lists.infradead.org