cmd_usage(): simplify return code handling

Lots of code use this construct:

	cmd_usage(cmdtp);
	return 1;

Change cmd_usage() let it return 1 - then we can replace all these
ocurrances by

	return cmd_usage(cmdtp);

This fixes a few places with incorrect return code handling, too.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/board/trizepsiv/eeprom.c b/board/trizepsiv/eeprom.c
index fede2e0..fd623df 100644
--- a/board/trizepsiv/eeprom.c
+++ b/board/trizepsiv/eeprom.c
@@ -42,36 +42,29 @@
 static int do_write_dm9000_eeprom ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) {
 	int offset,value;
 
-	if (argc < 4) {
-		cmd_usage(cmdtp);
-		return 1;
-	}
+	if (argc < 4)
+		return cmd_usage(cmdtp);
 
 	offset=simple_strtoul(argv[2],NULL,16);
 	value=simple_strtoul(argv[3],NULL,16);
 	if (offset > 0x40) {
 		printf("Wrong offset : 0x%x\n",offset);
-		cmd_usage(cmdtp);
-		return 1;
+		return cmd_usage(cmdtp);
 	}
 	dm9000_write_srom_word(offset, value);
 	return (0);
 }
 
 int do_dm9000_eeprom ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) {
-	if (argc < 2) {
-		cmd_usage(cmdtp);
-		return 1;
-	}
+	if (argc < 2)
+		return cmd_usage(cmdtp);
 
-	if (strcmp (argv[1],"read") == 0) {
+	if (strcmp (argv[1],"read") == 0)
 		return (do_read_dm9000_eeprom(cmdtp,flag,argc,argv));
-	} else if (strcmp (argv[1],"write") == 0) {
+	else if (strcmp (argv[1],"write") == 0)
 		return (do_write_dm9000_eeprom(cmdtp,flag,argc,argv));
-	} else {
-		cmd_usage(cmdtp);
-		return 1;
-	}
+	else
+		return cmd_usage(cmdtp);
 }
 
 U_BOOT_CMD(