drivers: ata: Mark the function as static in libahci.c

This patch marks the function ahci_port_intr() and
ahci_hw_port_interrupt() as static in libahci.c because they are not
used outside this file.

Thus, it also eliminates the following warnings in libahci.c:
drivers/ata/libahci.c:1767:6: warning: no previous prototype for ‘ahci_port_intr’ [-Wmissing-prototypes]
drivers/ata/libahci.c:1800:6: warning: no previous prototype for ‘ahci_hw_port_interrupt’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

drivers/ata/libahci.c

@@ -1764,7 +1764,7 @@ static void ahci_handle_port_interrupt(struct ata_port *ap,
 	}
 }
 
-void ahci_port_intr(struct ata_port *ap)
+static void ahci_port_intr(struct ata_port *ap)
 {
 	void __iomem *port_mmio = ahci_port_base(ap);
 	u32 status;
@@ -1797,7 +1797,7 @@ irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
 }
 EXPORT_SYMBOL_GPL(ahci_thread_fn);
 
-void ahci_hw_port_interrupt(struct ata_port *ap)
+static void ahci_hw_port_interrupt(struct ata_port *ap)
 {
 	void __iomem *port_mmio = ahci_port_base(ap);
 	struct ahci_port_priv *pp = ap->private_data;