Set an invalid quanta size from devargs will cause memory leak and this
is reported by coverity.
The patch fix the issue by correcting the error handle.
Coverity issue: 378017
Fixes: b14e8a57b9 ("net/iavf: support quanta size configuration")
Signed-off-by: Wenjun Wu <wenjun1.wu@intel.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>