Revert "ramster: switch over to zsmalloc and crypto interface"

This reverts commit 49b81a3c.

It causes build breakage under some configurations.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>