powerpc/crypto: rework Kconfig

This patch creates a new submenu for the NX cryptographic
hardware accelerator and breaks the NX options into their own
Kconfig file under drivers/crypto/nx/Kconfig.

This will permit additional NX functionality to be easily
and more cleanly added in the future without touching
drivers/crypto/Makefile|Kconfig.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/crypto/nx/Makefile b/drivers/crypto/nx/Makefile
index 411ce59..7f110e4 100644
--- a/drivers/crypto/nx/Makefile
+++ b/drivers/crypto/nx/Makefile
@@ -1,4 +1,4 @@
-obj-$(CONFIG_CRYPTO_DEV_NX) += nx-crypto.o
+obj-$(CONFIG_CRYPTO_DEV_NX_ENCRYPT) += nx-crypto.o
 nx-crypto-objs := nx.o \
 		  nx_debugfs.o \
 		  nx-aes-cbc.o \