[IPSEC]: Move linux/crypto.h inclusion out of net/xfrm.h

The header file linux/crypto.h is only needed by a few files so including
it in net/xfrm.h (which is included by half of the networking stack) is a
waste.  This patch moves it out of net/xfrm.h and into the specific header
files that actually need it.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/net/ipcomp.h

@@ -1,8 +1,12 @@
 #ifndef _NET_IPCOMP_H
 #define _NET_IPCOMP_H
 
+#include <linux/types.h>
+
 #define IPCOMP_SCRATCH_SIZE     65400
 
+struct crypto_tfm;
+
 struct ipcomp_data {
 	u16 threshold;
 	struct crypto_tfm **tfms;