modules: add missing module to ipsec description

Signed-off-by: Dirk Neukirchen <[email protected]>

package/kernel/linux/modules/netsupport.mk

@@ -300,6 +300,7 @@ define KernelPackage/ipsec/description
  Kernel modules for IPsec support in both IPv4 and IPv6.
  Includes:
  - af_key
+ - xfrm_algo
  - xfrm_ipcomp
  - xfrm_user
 endef