superio/fintek/f71859: Avoid .c includes

Following the same reasoning as commit
d304331 superio/fintek/f81865f: Avoid .c includes
Clean up the early_serial #include directives in mainboard/romstage code.

Change-Id: I3577ca3f761fb699dc51141a02e1f853bf1f1a21
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5417
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/mainboard/iei/kino-780am2-fam10/romstage.c

@@ -41,7 +41,7 @@
 #include "northbridge/amd/amdfam10/reset_test.c"
 #include <console/loglevel.h>
 #include "cpu/x86/bist.h"
-#include "superio/fintek/f71859/early_serial.c"
+#include <superio/fintek/f71859/f71859.h>
 #include <cpu/amd/mtrr.h>
 #include "northbridge/amd/amdfam10/setup_resource_map.c"
 #include "southbridge/amd/rs780/early_setup.c"

src/superio/fintek/f71859/Makefile.inc

@@ -18,5 +18,5 @@
 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 ##
 
+romstage-$(CONFIG_SUPERIO_FINTEK_F71859) += early_serial.c
 ramstage-$(CONFIG_SUPERIO_FINTEK_F71859) += superio.c
-

src/superio/fintek/f71859/early_serial.c

@@ -21,6 +21,7 @@
 /* Pre-RAM driver for the Fintek F71859 Super I/O chip. */
 
 #include <arch/io.h>
+#include <device/pnp.h>
 #include "f71859.h"
 
 static void pnp_enter_conf_state(device_t dev)
@@ -36,7 +37,7 @@ static void pnp_exit_conf_state(device_t dev)
 	outb(0xaa, port);
 }
 
-static void f71859_enable_serial(device_t dev, u16 iobase)
+void f71859_enable_serial(device_t dev, u16 iobase)
 {
 	pnp_enter_conf_state(dev);
 	pnp_set_logical_device(dev);

src/superio/fintek/f71859/f71859.h

@@ -24,4 +24,6 @@
 /* Logical Device Numbers (LDN). */
 #define F71859_SP1	0x03	/* UART1 */
 
-#endif
+void f71859_enable_serial(device_t dev, u16 iobase);
+
+#endif /* SUPERIO_FINTEK_F71859_F71859_H */