9p: fix debug build error

Fixes build problem with 9p when building with debug disabled.
Also contains some fixes for warnings which pop up when 
CONFIG_NET_9P_DEBUG is disabled.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>


diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index d2c60c7..b77c147 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -56,9 +56,9 @@
 	P9_DEBUG_PKT =		(1<<10),
 };
 
+#ifdef CONFIG_NET_9P_DEBUG
 extern unsigned int p9_debug_level;
 
-#ifdef CONFIG_NET_9P_DEBUG
 #define P9_DPRINTK(level, format, arg...) \
 do {  \
 	if ((p9_debug_level & level) == level) {\