disk: define HAVE_BLOCK_DEVICE in a common place

This set of ifdefs is used in a number of places. Move its definition
somewhere common so it doesn't have to be repeated.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Acked-by: Tom Rini <trini@ti.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/disk/part_amiga.c b/disk/part_amiga.c
index dc7d462..0e6d82d 100644
--- a/disk/part_amiga.c
+++ b/disk/part_amiga.c
@@ -26,11 +26,7 @@
 #include <ide.h>
 #include "part_amiga.h"
 
-#if defined(CONFIG_CMD_IDE) || \
-    defined(CONFIG_CMD_SCSI) || \
-    defined(CONFIG_CMD_USB) || \
-    defined(CONFIG_MMC) || \
-    defined(CONFIG_SYSTEMACE)
+#ifdef HAVE_BLOCK_DEVICE
 
 #undef AMIGA_DEBUG