ixgbe: use IS_ENABLED() instead of checking for built-in or module

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.

Using the macro makes the code more readable by helping abstract away some
of the Kconfig built-in and module enable details.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -45,10 +45,10 @@
 #include "ixgbe_type.h"
 #include "ixgbe_common.h"
 #include "ixgbe_dcb.h"
-#if defined(CONFIG_FCOE) || defined(CONFIG_FCOE_MODULE)
+#if IS_ENABLED(CONFIG_FCOE)
 #define IXGBE_FCOE
 #include "ixgbe_fcoe.h"
-#endif /* CONFIG_FCOE or CONFIG_FCOE_MODULE */
+#endif /* IS_ENABLED(CONFIG_FCOE) */
 #ifdef CONFIG_IXGBE_DCA
 #include <linux/dca.h>
 #endif