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/board/freescale/m5253demo/m5253demo.c b/board/freescale/m5253demo/m5253demo.c
index c2cc2d7..3318368 100644
--- a/board/freescale/m5253demo/m5253demo.c
+++ b/board/freescale/m5253demo/m5253demo.c
@@ -88,7 +88,7 @@
 	return (0);
 }
 
-#ifdef CONFIG_CMD_IDE
+#ifdef CONFIG_IDE
 #include <ata.h>
 int ide_preinit(void)
 {
@@ -133,7 +133,7 @@
 		setbits_8(&ata->cr, 0x01);
 	}
 }
-#endif				/* CONFIG_CMD_IDE */
+#endif				/* CONFIG_IDE */
 
 
 #ifdef CONFIG_DRIVER_DM9000