net: cosmetic: Clean up DNS variables and functions

Make a thorough pass through all variables and function names contained
within dns.c and remove CamelCase and improve naming.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/net/dns.h b/net/dns.h
index dbc3890..c4e96af 100644
--- a/net/dns.h
+++ b/net/dns.h
@@ -31,6 +31,6 @@
 	unsigned char	data[1];	/* Data, variable length */
 };
 
-extern void DnsStart(void);		/* Begin DNS */
+void dns_start(void);		/* Begin DNS */
 
 #endif