block: fix CDROM dependency on BLK_DEV

After the cdrom cleanup, I get randconfig warnings for some configurations:

warning: (BLK_DEV_IDECD && BLK_DEV_SR) selects CDROM which has unmet direct dependencies (BLK_DEV)

This adds an explicit BLK_DEV dependency for both drivers. The other
drivers that select 'CDROM' already have this and don't need a change.

Fixes: 2a750166a5be ("block: Rework drivers/cdrom/Makefile")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/ide/Kconfig

@@ -117,6 +117,7 @@ config BLK_DEV_DELKIN
 
 config BLK_DEV_IDECD
 	tristate "Include IDE/ATAPI CDROM support"
+	depends on BLK_DEV
 	select IDE_ATAPI
 	select CDROM
 	---help---

drivers/scsi/Kconfig

@@ -130,7 +130,7 @@ config CHR_DEV_OSST
 
 config BLK_DEV_SR
 	tristate "SCSI CDROM support"
-	depends on SCSI
+	depends on SCSI && BLK_DEV
 	select CDROM
 	---help---
 	  If you want to use a CD or DVD drive attached to your computer