net: remove duplicate definition of ETHADDR_WILDCARD

ETHADDR_WILDCARD is defined as the same value in both env_flags.h
and env_callback.h

As env_callback.h includes env_flags.h, remove the duplicate definition
from env_callback.h

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/include/env_callback.h b/include/env_callback.h
index 3c44ff5..507a52e 100644
--- a/include/env_callback.h
+++ b/include/env_callback.h
@@ -32,10 +32,8 @@
 
 #ifdef CONFIG_REGEX
 #define ENV_DOT_ESCAPE "\\"
-#define ETHADDR_WILDCARD "\\d?"
 #else
 #define ENV_DOT_ESCAPE
-#define ETHADDR_WILDCARD
 #endif
 
 #ifdef CONFIG_CMD_DNS