libata: Fix Cell SATA driver dependencies

The driver requires in_be32(), and so should not be built on many PCI
platforms.
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/Kconfig

@@ -564,7 +564,7 @@ config PATA_IXP4XX_CF
 
 config PATA_SCC
 	tristate "Toshiba's Cell Reference Set IDE support"
-	depends on PCI
+	depends on PCI && PPC_IBM_CELL_BLADE
 	help
 	  This option enables support for the built-in IDE controller on
 	  Toshiba Cell Reference Board.