powerpc/crypto: add 842 crypto driver

This patch add the 842 cryptographic API driver that
submits compression requests to the 842 hardware compression
accelerator driver (nx-compress).

If the hardware accelerator goes offline for any reason
(dynamic disable, migration, etc...), this driver will use LZO
as a software failover for all future compression requests.
For decompression requests, the 842 hardware driver contains
a software implementation of the 842 decompressor to support
the decompression of data that was compressed before the accelerator
went offline.

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/crypto/Kconfig b/crypto/Kconfig
index fe8ed62..cbcc0e2 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1039,6 +1039,15 @@
 	help
 	  This is the LZO algorithm.
 
+config CRYPTO_842
+	tristate "842 compression algorithm"
+	depends on CRYPTO_DEV_NX_COMPRESS
+	# 842 uses lzo if the hardware becomes unavailable
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+	help
+	  This is the 842 algorithm.
+
 comment "Random Number Generation"
 
 config CRYPTO_ANSI_CPRNG