ide: make 'extra' field in struct ide_port_info u8

The maximum value used currently for 'extra' field in struct ide_port_info
is 240.

Make 'extra' u8 so it packs nicely together with enablebits[] and 'chipset'
fields (ide_pci_enablebit_t is 3 bytes and hwif_chipset_t is 1 byte).
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

include/linux/ide.h

@@ -1111,7 +1111,7 @@ struct ide_port_info {
 	void			(*fixup)(ide_hwif_t *);
 	ide_pci_enablebit_t	enablebits[2];
 	hwif_chipset_t		chipset;
-	unsigned int		extra;
+	u8			extra;
 	u32			host_flags;
 	u8			pio_mask;
 	u8			swdma_mask;