[LIBNL]: Fix format strings

Use %td for ptrdiff_t and %zu for size_t.

Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/lib/msg.c b/lib/msg.c
index d19ac08..cacc773 100644
--- a/lib/msg.c
+++ b/lib/msg.c
@@ -363,7 +363,7 @@
 	nm->nm_protocol = -1;
 	nm->nm_nlh->nlmsg_len = len;
 
-	NL_DBG(2, "msg %p: Allocated new message, nlmsg_len=%d\n", nm, len);
+	NL_DBG(2, "msg %p: Allocated new message, nlmsg_len=%zu\n", nm, len);
 
 	return nm;
 errout:
@@ -494,7 +494,7 @@
 	if (tlen > len)
 		memset(tmp + len, 0, tlen - len);
 
-	NL_DBG(2, "msg %p: Reserved %d bytes, pad=%d, nlmsg_len=%d\n",
+	NL_DBG(2, "msg %p: Reserved %zu bytes, pad=%d, nlmsg_len=%d\n",
 		  n, len, pad, n->nm_nlh->nlmsg_len);
 
 	return tmp;
@@ -524,7 +524,7 @@
 		return nl_errno(ENOMEM);
 
 	memcpy(tmp, data, len);
-	NL_DBG(2, "msg %p: Appended %d bytes with padding %d\n", n, len, pad);
+	NL_DBG(2, "msg %p: Appended %zu bytes with padding %d\n", n, len, pad);
 
 	return 0;
 }