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/common/cmd_fpga.c b/common/cmd_fpga.c
index ddc7a05..e50c9de 100644
--- a/common/cmd_fpga.c
+++ b/common/cmd_fpga.c
@@ -44,7 +44,6 @@
 #endif
 
 /* Local functions */
-static void fpga_usage (cmd_tbl_t * cmdtp);
 static int fpga_get_op (char *opstr);
 
 /* Local defines */
@@ -232,8 +231,7 @@
 
 	switch (op) {
 	case FPGA_NONE:
-		fpga_usage (cmdtp);
-		break;
+		return cmd_usage(cmdtp);
 
 	case FPGA_INFO:
 		rc = fpga_info (dev);
@@ -312,17 +310,11 @@
 
 	default:
 		printf ("Unknown operation\n");
-		fpga_usage (cmdtp);
-		break;
+		return cmd_usage(cmdtp);
 	}
 	return (rc);
 }
 
-static void fpga_usage (cmd_tbl_t * cmdtp)
-{
-	cmd_usage(cmdtp);
-}
-
 /*
  * Map op to supported operations.  We don't use a table since we
  * would just have to relocate it from flash anyway.