ixgbe: inline the ixgbe_maybe_stop_tx function

The ixgbe_maybe_stop_tx function is only a few lines long and is called
multiple times through the xmit hotpath.  In order to streamline things it
makes sense to just inline it.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ixgbe/ixgbe_main.c

@@ -6785,7 +6785,7 @@ static int __ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)
 	return 0;
 }
 
-static int ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)
+static inline int ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)
 {
 	if (likely(ixgbe_desc_unused(tx_ring) >= size))
 		return 0;