[PATCH 1_4] Merge common get_dev() routines for block devices

Each of the filesystem drivers duplicate the get_dev routine.  This change
merges them into a single function in part.c

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/common/cmd_usb.c b/common/cmd_usb.c
index 28c05aa..904df71 100644
--- a/common/cmd_usb.c
+++ b/common/cmd_usb.c
@@ -28,6 +28,7 @@
 #include <common.h>
 #include <command.h>
 #include <asm/byteorder.h>
+#include <part.h>
 
 #if (CONFIG_COMMANDS & CFG_CMD_USB)