Propagate Error Status to the Shell on fw_printenv Errors

Changed implementation such that fw_printenv returns failure status
when one or more specified variables do not exist or when incorrect
command syntax is used.

This aids scripting fw_printenv such that the script can key of the
return status rather than relying on standard error "scraping".

Signed-off-by: Grant Erickson <gerickson@nuovations.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/tools/env/fw_env.h b/tools/env/fw_env.h
index 58607de..248f58c 100644
--- a/tools/env/fw_env.h
+++ b/tools/env/fw_env.h
@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2002
+ * (C) Copyright 2002-2008
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  *
  * See file CREDITS for list of people who contributed to this
@@ -47,7 +47,7 @@
 	"ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}::off; " 	\
 	"bootm"
 
-extern void  fw_printenv(int argc, char *argv[]);
+extern int   fw_printenv(int argc, char *argv[]);
 extern char *fw_getenv  (char *name);
 extern int fw_setenv  (int argc, char *argv[]);