netlink: Move netlink attribute parsing support to lib

Netlink attribute parsing may be used even if CONFIG_NET is not set.
Move it from net/netlink to lib and control its inclusion based on the new
config symbol CONFIG_NLATTR, which is selected by CONFIG_NET.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/lib/Makefile b/lib/Makefile
index 32b0e64..b2c09da 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -84,6 +84,8 @@
 
 obj-$(CONFIG_DYNAMIC_PRINTK_DEBUG) += dynamic_printk.o
 
+obj-$(CONFIG_NLATTR) += nlattr.o
+
 hostprogs-y	:= gen_crc32table
 clean-files	:= crc32table.h