blk: Make block subsystems select BLK

The BLK symbol has a few meanings, one of which is that it controls the
driver model portion of a "block device". Rather than having this hidden
symbol be "default y if ..." it should be select'd by the various block
subsystems. Symbols such as PVBLOCK which already select'd BLK are
unchanged".

Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Tom Rini <trini@konsulko.com>

drivers/ata/Kconfig

@@ -1,6 +1,7 @@
 config AHCI
 	bool "Support SATA controllers with driver model"
 	depends on DM
+	select BLK
 	help
 	  This enables a uclass for disk controllers in U-Boot. Various driver
 	  types can use this, such as AHCI/SATA. It does not provide any standard
@@ -9,6 +10,7 @@ config AHCI
 
 config SATA
 	bool "Support SATA controllers"
+	select BLK
 	help
 	  This enables support for SATA (Serial Advanced Technology
 	  Attachment), a serial bus standard for connecting to hard drives and