udhcp: add setup_common_bufsiz() as needed

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 660b943..8f5a03f 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -1268,6 +1268,8 @@
 	int retval;
 	fd_set rfds;
 
+	setup_common_bufsiz();
+
 	/* Default options */
 	IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
 	IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)