ide: Move ATA_CURR_BASE to C file

This is not used outside one C file. Move it out of the header to
reduce its visbility.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/block/ide.c b/drivers/block/ide.c
index 1ad9b6c..f36bec8 100644
--- a/drivers/block/ide.c
+++ b/drivers/block/ide.c
@@ -36,6 +36,9 @@
 #endif
 };
 
+#define ATA_CURR_BASE(dev)	(CONFIG_SYS_ATA_BASE_ADDR + \
+		ide_bus_offset[IDE_BUS(dev)])
+
 static int ide_bus_ok[CONFIG_SYS_IDE_MAXBUS];
 
 struct blk_desc ide_dev_desc[CONFIG_SYS_IDE_MAXDEVICE];