[PATCH] add Big Endian variants of ioread/iowrite

In the new io infrastructure, all of our operators are expecting the
underlying device to be little endian (because the PCI bus, their main
consumer, is LE).

However, there are a fair few devices and busses in the world that are
actually Big Endian.  There's even evidence that some of these BE bus and
chip types are attached to LE systems.  Thus, there's a need for a BE
equivalent of our io{read,write}{16,32} operations.

The attached patch adds this as io{read,write}{16,32}be.  When it's in,
I'll add the first consume (the 53c700 SCSI chip driver).

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>