staging: zcache: fix Kconfig crypto dependency

ZCACHE is a boolean in the Kconfig.  When selected, it
should require that CRYPTO be builtin (=y).

Currently, ZCACHE=y and CRYPTO=m is a valid configuration
when it should not be.

This patch changes the zcache Kconfig to enforce this
dependency.
Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/zcache/Kconfig

@@ -2,7 +2,7 @@ config ZCACHE
 	bool "Dynamic compression of swap pages and clean pagecache pages"
 	# X86 dependency is because zsmalloc uses non-portable pte/tlb
 	# functions
-	depends on (CLEANCACHE || FRONTSWAP) && CRYPTO && X86
+	depends on (CLEANCACHE || FRONTSWAP) && CRYPTO=y && X86
 	select ZSMALLOC
 	select CRYPTO_LZO
 	default n