udhcp: change UDHCP_DEBUG into int, make verbosity selectable with -v

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

networking/udhcp/common.c

@@ -3,9 +3,12 @@
  *
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
-
 #include "common.h"
 
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+int dhcp_verbose;
+#endif
+
 const uint8_t MAC_BCAST_ADDR[6] ALIGN2 = {
 	0xff, 0xff, 0xff, 0xff, 0xff, 0xff
 };