1. Removed logic to update HW producer index in interrupt context.

2. Update HW producer index after UIO ring and buffer gets initialized.
Signed-off-by: Manish Rangankar <manish.rangankar@cavium.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>