ixgbe: Remove unused inline function ixgbe_irq_disable_queues

commit b5f69ccf

 ("ixgbe: avoid bringing rings up/down as macvlans are added/removed")
left behind this, remove it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>