ixgbe: fix namespace issues when FCoE/DCB is not enabled

Resolve namespace issues when FCoE or DCB is not enabled.
The issue is with certain configurations we end up with namespace
problems. A simple example:

ixgbe_main.c
 - defines func A()
 - uses func A()

ixgbe_fcoe.c
 - uses func A()

ixgbe.h
 - has prototype for func A()

For default (FCoE included) all is good.  But when it isn't the namespace
checker complains about how func A() could be static.

To resolve this, created a ixgbe_lib file to contain functions used
by DCB/FCoE and their helper functions so that they are always in
namespace whether or not DCB/FCoE is enabled.
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>

drivers/net/ethernet/intel/ixgbe/Makefile

@@ -34,7 +34,7 @@ obj-$(CONFIG_IXGBE) += ixgbe.o
 
 ixgbe-objs := ixgbe_main.o ixgbe_common.o ixgbe_ethtool.o \
               ixgbe_82599.o ixgbe_82598.o ixgbe_phy.o ixgbe_sriov.o \
-              ixgbe_mbx.o ixgbe_x540.o
+              ixgbe_mbx.o ixgbe_x540.o ixgbe_lib.o
 
 ixgbe-$(CONFIG_IXGBE_DCB) +=  ixgbe_dcb.o ixgbe_dcb_82598.o \
                               ixgbe_dcb_82599.o ixgbe_dcb_nl.o

drivers/net/ethernet/intel/ixgbe/ixgbe.h

@@ -581,7 +581,9 @@ extern int ixgbe_copy_dcb_cfg(struct ixgbe_dcb_config *src_dcb_cfg,
 
 extern char ixgbe_driver_name[];
 extern const char ixgbe_driver_version[];
+#ifdef IXGBE_FCOE
 extern char ixgbe_default_device_descr[];
+#endif /* IXGBE_FCOE */
 
 extern void ixgbe_up(struct ixgbe_adapter *adapter);
 extern void ixgbe_down(struct ixgbe_adapter *adapter);
@@ -606,6 +608,7 @@ extern void ixgbe_unmap_and_free_tx_resource(struct ixgbe_ring *,
                                              struct ixgbe_tx_buffer *);
 extern void ixgbe_alloc_rx_buffers(struct ixgbe_ring *, u16);
 extern void ixgbe_write_eitr(struct ixgbe_q_vector *);
+extern int ixgbe_poll(struct napi_struct *napi, int budget);
 extern int ethtool_ioctl(struct ifreq *ifr);
 extern s32 ixgbe_reinit_fdir_tables_82599(struct ixgbe_hw *hw);
 extern s32 ixgbe_init_fdir_signature_82599(struct ixgbe_hw *hw, u32 fdirctrl);
@@ -625,7 +628,9 @@ extern s32 ixgbe_fdir_erase_perfect_filter_82599(struct ixgbe_hw *hw,
 extern void ixgbe_atr_compute_perfect_hash_82599(union ixgbe_atr_input *input,
 						 union ixgbe_atr_input *mask);
 extern void ixgbe_set_rx_mode(struct net_device *netdev);
+#ifdef CONFIG_IXGBE_DCB
 extern int ixgbe_setup_tc(struct net_device *dev, u8 tc);
+#endif
 extern void ixgbe_tx_ctxtdesc(struct ixgbe_ring *, u32, u32, u32, u32);
 extern void ixgbe_do_reset(struct net_device *netdev);
 #ifdef IXGBE_FCOE