udhcp: logging improvements, field and variable renames

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
index c44f382..4de29f2 100644
--- a/networking/udhcp/common.c
+++ b/networking/udhcp/common.c
@@ -6,7 +6,7 @@
 #include "common.h"
 
 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
-int dhcp_verbose;
+unsigned dhcp_verbose;
 #endif
 
 const uint8_t MAC_BCAST_ADDR[6] ALIGN2 = {