Kconfig: Add a CONFIG_IDE option

At present IDE support is controlled by CONFIG_CMD_IDE. Add a separate
CONFIG_IDE option so that IDE support can be enabled without requiring
the 'ide' command.

Update existing users and move the ide driver into drivers/block since
it should not be in common/.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/M5253DEMO.h b/include/configs/M5253DEMO.h
index e7c6f8b..3efd7e5 100644
--- a/include/configs/M5253DEMO.h
+++ b/include/configs/M5253DEMO.h
@@ -38,7 +38,7 @@
  * Command line configuration.
  */
 
-#ifdef CONFIG_CMD_IDE
+#ifdef CONFIG_IDE
 /* ATA */
 #	define CONFIG_IDE_RESET		1
 #	define CONFIG_IDE_PREINIT	1