sparc: Fix parport build warnings.

If PARPORT_PC_FIFO is not enabled, do not provide the dma lock
macros and lock definition.  Otherwise:

./arch/sparc/include/asm/parport.h:24:24: warning: ‘dma_spin_lock’ defined but not used [-Wunused-variable]
 static DEFINE_SPINLOCK(dma_spin_lock);
                        ^~~~~~~~~~~~~
./include/linux/spinlock_types.h:81:39: note: in definition of macro ‘DEFINE_SPINLOCK’
 #define DEFINE_SPINLOCK(x) spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/parport.h

@@ -21,6 +21,7 @@
  */
 #define HAS_DMA
 
+#ifdef CONFIG_PARPORT_PC_FIFO
 static DEFINE_SPINLOCK(dma_spin_lock);
 
 #define claim_dma_lock() \
@@ -31,6 +32,7 @@ static DEFINE_SPINLOCK(dma_spin_lock);
 
 #define release_dma_lock(__flags) \
 	spin_unlock_irqrestore(&dma_spin_lock, __flags);
+#endif
 
 static struct sparc_ebus_info {
 	struct ebus_dma_info info;