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/config_fallbacks.h b/include/config_fallbacks.h
index 7aa5b02..5a698a8 100644
--- a/include/config_fallbacks.h
+++ b/include/config_fallbacks.h
@@ -43,7 +43,7 @@
 #endif
 
 /* Rather than repeat this expression each time, add a define for it */
-#if defined(CONFIG_CMD_IDE) || \
+#if defined(CONFIG_IDE) || \
 	defined(CONFIG_CMD_SATA) || \
 	defined(CONFIG_SCSI) || \
 	defined(CONFIG_CMD_USB) || \