Use traditional error check pattern
	ret = ...;
	if (ret)
		return ret;
	...
instead of checking error code to be 0.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>