[S390] tape block: fix dependencies

  CC      drivers/s390/char/tape_block.o
In file included from drivers/s390/char/tape_block.c:24:
drivers/s390/char/tape.h:159: warning: 'struct request' declared inside
parameter list

Adding the dependency of CONFIG_BLOCK to CONFIG_S390_TAPE_BLOCK.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/Kconfig

@@ -100,7 +100,7 @@ comment "S/390 tape interface support"
 
 config S390_TAPE_BLOCK
 	bool "Support for tape block devices"
-	depends on S390_TAPE
+	depends on S390_TAPE && BLOCK
 	help
 	  Select this option if you want to access your channel-attached tape
 	  devices using the block device interface.  This interface is similar