igb: add PF to pool

Add Pf to pool if adding a VLVF register value and the VFTA bit is
already set.

This patch addresses the unlikely situation that the PF adds a vlan
entry when the vlvf is full, and a vf later adds the vlan to the vlvf.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/igb/e1000_mac.h

@@ -58,7 +58,7 @@ s32  igb_write_8bit_ctrl_reg(struct e1000_hw *hw, u32 reg,
 
 void igb_clear_hw_cntrs_base(struct e1000_hw *hw);
 void igb_clear_vfta(struct e1000_hw *hw);
-void igb_vfta_set(struct e1000_hw *hw, u32 vid, bool add);
+s32  igb_vfta_set(struct e1000_hw *hw, u32 vid, bool add);
 void igb_config_collision_dist(struct e1000_hw *hw);
 void igb_mta_set(struct e1000_hw *hw, u32 hash_value);
 void igb_put_hw_semaphore(struct e1000_hw *hw);