nfp: Use spinlock_t instead of struct spinlock

For spinlocks the type spinlock_t should be used instead of "struct
spinlock".

Use spinlock_t for spinlock's definition.

Cc: Jakub Kicinski <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Acked-by: Jakub Kicinski <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/netronome/nfp/nfp_net.h

···
 		struct {
 			struct tasklet_struct tasklet;
 			struct sk_buff_head queue;
-			struct spinlock lock;
+			spinlock_t lock;
 		};
 	};