powerpc/crypto: add 842 hardware compression driver

This patch adds the driver for interacting with the 842
compression accelerator on IBM Power7+ systems.

The device is a child of the Platform Facilities Option (PFO)
and shows up as a child of the IBM VIO bus.

The compression/decompression API takes the same arguments
as existing compression methods like lzo and deflate.  The 842
hardware operates on 4K hardware pages and the driver breaks up
input on 4K boundaries to submit it to the hardware accelerator.

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/MAINTAINERS b/MAINTAINERS
index 6720018..f2dfb20 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3415,6 +3415,12 @@
 S:	Maintained
 F:	arch/ia64/
 
+IBM Power 842 compression accelerator
+M:	Robert Jennings <rcj@linux.vnet.ibm.com>
+S:	Supported
+F:	drivers/crypto/nx/nx-842.c
+F:	include/linux/nx842.h
+
 IBM Power Linux RAID adapter
 M:	Brian King <brking@us.ibm.com>
 S:	Supported