Value of count is used to decide when to replenish rx buffers. If it is
equal or above 8 we replenish the buffers. Ensure there is no starvation
by initializing count to 8 - thus forcing replenish at first iteration.

This is helpful when rx receives batches of buffers smaller than 8.
Signed-off-by: NMohamed Abbas <mabbas@linux.intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>