powerpc: Make macintosh/mediabay driver depend on CONFIG_BLOCK

Fixes this build error:

In file included from drivers/macintosh/mediabay.c:21:
include/linux/ide.h:605: error: field 'request_sense_rq' has incomplete type
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

drivers/macintosh/Kconfig

@@ -123,7 +123,7 @@ config PMAC_APM_EMU
 
 config PMAC_MEDIABAY
 	bool "Support PowerBook hotswap media bay"
-	depends on PPC_PMAC && PPC32
+	depends on PPC_PMAC && PPC32 && BLOCK
 	help
 	  This option adds support for older PowerBook's hotswap media bay
 	  that can contains batteries, floppy drives, or IDE devices. PCI