libata-transport.c: local functions should not be exposed globally

Functions not referenced outside of a source file should be marked
static to prevent it from being exposed globally.

This quiets the sparse warnings:

warning: symbol 'ata_is_port' was not declared. Should it be static?
warning: symbol 'ata_is_link' was not declared. Should it be static?
warning: symbol 'ata_is_ata_dev' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-transport.c

@@ -232,7 +232,7 @@ static void ata_tport_release(struct device *dev)
  * Returns:
  *	%1 if the device represents a ATA Port, %0 else
  */
-int ata_is_port(const struct device *dev)
+static int ata_is_port(const struct device *dev)
 {
 	return dev->release == ata_tport_release;
 }
@@ -355,7 +355,7 @@ static void ata_tlink_release(struct device *dev)
  * Returns:
  *	%1 if the device represents a ATA link, %0 else
  */
-int ata_is_link(const struct device *dev)
+static int ata_is_link(const struct device *dev)
 {
 	return dev->release == ata_tlink_release;
 }
@@ -572,7 +572,7 @@ static void ata_tdev_release(struct device *dev)
  * Returns:
  *	%1 if the device represents a ATA device, %0 else
  */
-int ata_is_ata_dev(const struct device *dev)
+static int ata_is_ata_dev(const struct device *dev)
 {
 	return dev->release == ata_tdev_release;
 }