Change return value on error.

On wrong parameters a error is signalized to the calling function.

Change-Id: I484443fdb39938e20382edc9246d5ec546a5c960
Signed-off-by: Mathias K <kesmtp@freenet.de>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>
Reviewed-on: http://openocd.zylin.com/282
Tested-by: jenkins
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>

src/flash/nand/lpc3180.c

@@ -45,8 +45,7 @@ NAND_DEVICE_COMMAND_HANDLER(lpc3180_nand_device_command)
 {
 	if (CMD_ARGC < 3)
 	{
-		LOG_WARNING("incomplete 'lpc3180' nand flash configuration");
-		return ERROR_FLASH_BANK_INVALID;
+		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
 	uint32_t osc_freq;