SSFDC must depend on BLOCK

This patch fixes the following compile error with
CONFIG_SSFDC=m, CONFIG_BLOCK=n:

<-- snip -->

...
CC [M] drivers/mtd/mtd_blkdevs.o
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c:40: warning: ‘struct request’ declared inside parameter list /home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c:40: warning: its scope is only this definition or declaration, which is probably not what you want /home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c: In function ‘do_blktrans_request’:
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c:45: error: dereferencing pointer to incomplete type
...
make[3]: *** [drivers/mtd/mtd_blkdevs.o] Error 1

<-- snip -->

Bug report by Jesper Juhl.

This patch also removes a pointless "default n" from the SSFDC option.

@@ -265,8 +265,7 @@
 
 config SSFDC
 	tristate "NAND SSFDC (SmartMedia) read only translation layer"
-	depends on MTD
-	default n
+	depends on MTD && BLOCK
 	help
 	  This enables read only access to SmartMedia formatted NAND
 	  flash. You can mount it with FAT file system.