libceph: add ceph_decode_entity_addr

Add a function for decoding an entity_addr_t. Once
CEPH_FEATURE_MSG_ADDR2 is enabled, the server daemons will start
encoding entity_addr_t differently.

Add a new helper function that can handle either format.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/net/ceph/Makefile b/net/ceph/Makefile
index db09defe..59d0ba2 100644
--- a/net/ceph/Makefile
+++ b/net/ceph/Makefile
@@ -5,7 +5,7 @@
 obj-$(CONFIG_CEPH_LIB) += libceph.o
 
 libceph-y := ceph_common.o messenger.o msgpool.o buffer.o pagelist.o \
-	mon_client.o \
+	mon_client.o decode.o \
 	cls_lock_client.o \
 	osd_client.o osdmap.o crush/crush.o crush/mapper.o crush/hash.o \
 	striper.o \